MRSA Rate Research Articles

1320. In Vitro Activity of Lefamulin against Staphylococcus aureus Isolated from the Lower Respiratory Tract of Children with Cystic Fibrosis

BackgroundLefamulin is a first-in-class, oral and IV pleuromutilin antibiotic approved in the US, EU, and Canada for the treatment of community-acquired bacterial pneumonia (CABP) in adults. Lefamulin inhibits bacterial protein synthesis via a unique mechanism of action and its potency against S. aureus has been well established. We evaluated the in vitro activity of lefamulin against S. aureus from patients with cystic fibrosis (CF). MethodsUnique isolates (n=224) were collected from the lower respiratory tract (LRT) of children (≤17 years old) with CF and LRT infection. Organisms were from qualified respiratory specimens and determined to be the probable cause of infection by the participant center. The isolates were collected in 2018-2020 from 22 medical centers in 11 countries and tested by broth microdilution methods at JMI Laboratories. Most isolates were from the US (43.3%), Spain (24.1%), France (20.5%), and Costa Rica (7.1%). ResultsLefamulin was highly active against the CF S. aureus collection (MIC5090, 0.06/0.12 mg/L), with 99.6% of isolates inhibited at ≤0.25 mg/L, consistent with the susceptible [S] breakpoint published by the US FDA, CLSI, and EUCAST. Only 1 lefamulin-non-S (MIC, 1 mg/L) isolate was observed, a methicillin-susceptible (MSSA) collected in Costa Rica in 2018 and carrying a vga(A) gene. Lefamulin retained potent activity against methicillin-resistant (R) S. aureus (MRSA, n=52; MIC50/90, 0.06/0.12 mg/L), azithromycin-R (n=115; MIC50/90, 0.06/0.12 mg/L), levofloxacin-R (n=23; MIC50/90, 0.06/0.12 mg/L), clindamycin-R (n=11; MIC50/90, 0.06/0.12 mg/L), and gentamicin-R (n=9; MIC range of 0.03-0.12 mg/L) isolates as well as those isolates with multiple resistance phenotypes. Against MRSA, susceptibility to azithromycin was 23.5% and to levofloxacin 64.7%. All isolates were susceptible to vancomycin, linezolid and ceftaroline (Table). Among isolates from the US (n=97), the MRSA rate was 30.9% and all isolates were Lefamulin-S (MIC5090, 0.06/0.12 mg/L).ConclusionLefamulin demonstrated potent in vitro antibacterial activity against S. aureus from children with CF, regardless of resistance phenotype. Lefamulin may represent a valuable treatment option for CF patients with S. aureus LRT infections. Disclosures Helio S. Sader, MD, PhD, FIDSA, AbbVie (formerly Allergan) (Research Grant or Support)Basilea Pharmaceutica International, Ltd. (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)Department of Health and Human Services (Research Grant or Support, Contract no. HHSO100201600002C)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Susanne Paukner, PhD, Nabriva Therapeutics GmbH (Employee) Steven P. Gelone, PharmD, Nabriva Therapeutics US, Inc. (Employee) S J Ryan Arends, PhD, AbbVie (formerly Allergan) (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Spero Therapeutics (Research Grant or Support) Rodrigo E. Mendes, PhD, AbbVie (Research Grant or Support)AbbVie (formerly Allergan) (Research Grant or Support)Cipla Therapeutics (Research Grant or Support)Cipla USA Inc. (Research Grant or Support)ContraFect Corporation (Research Grant or Support)GlaxoSmithKline, LLC (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, LLC (Research Grant or Support)Nabriva Therapeutics (Research Grant or Support)Pfizer, Inc. (Research Grant or Support)Shionogi (Research Grant or Support)Spero Therapeutics (Research Grant or Support)

Trends in antimicrobial resistance in bloodstream infections at a large tertiary-care hospital in China: a 10-year retrospective study (2010–2019)

Bloodstream infections (BSIs) are a major cause of morbidity and mortality worldwide. This study aimed to explore the distribution and antimicrobial resistance of BSI pathogens at a tertiary-care hospital in China. Surveillance blood cultures were routinely taken from patients with fever or suspected sepsis from 2010-2019 at the First Affiliated Hospital of Zhengzhou University. Isolate identification was performed by VITEK®2 Compact and/or VITEK® MS. Antimicrobial susceptibility testing was carried out by MIC determination and/or disk diffusion. Totally, 18 180 strains were isolated from blood cultures, the most common being Escherichia coli (21.7%), followed by coagulase-negative staphylococci (CoNS) (18.8%), Klebsiella pneumoniae (13.0%) and Staphylococcus aureus (6.6%). Escherichia coli resistance rates to ceftazidime, ceftriaxone, cefepime and aztreonam showed a significant declining trend, and the frequency of carbapenem-resistant E. coli was <6.0% over time. Noteworthy, the proportion of carbapenem-resistant K. pneumoniae exhibited a sharp upward trend (from 6.7% to 56.7%). The prevalence of carbapenem-resistant A. baumannii remained at a high level (>75%). Pseudomonas aeruginosa resistance rates against all tested agents were <25%, and resistance rates to aminoglycosides and fluoroquinolones showed a significant downward trend. The frequency of methicillin-resistant CoNS maintained a high level (>70%), however the isolation rate of MRSA ranged from 58.0% to 34.7%, showing a significant decline. The dramatic increase in carbapenem-resistant K. pneumoniae during 10 years was noteworthy. Effective infection control measures and stewardship efforts should be taken to prevent their spread. Our results indicate the importance of active surveillance for aetiology and resistance of BSI isolates.

Abstract 13899: Isolated Tricuspid Valve Endocarditis Within A Patient Population At High Risk Of Intravenous Drug Use: A Retrospective Cohort Study

Introduction: Tricuspid valve endocarditis (TVE) is associated with intravenous drug use (IVDU) and complicated by numerous disease processes and societal impacts. Our academic medical center treats many TVE patients, predominantly with history of IVDU. We hypothesize that adverse outcomes related to TVE are associated with myriad co-morbidities and that a multidisciplinary approach integrating addiction medicine may improve outcomes and decrease in-hospital mortality. Methods: We conducted a medical record query of patients found to have infective endocarditis involving only the tricuspid valve and treated between July 2018 and January 2021. Baseline demographic data, characteristics and complications of TVE, echocardiographic data, and clinical outcomes were measured. Results: A total of 73 TVE patients were included; 32 were male, 41 were female. Mean age was 36.6 ± 11.8 years. Fifty (68%) patients reported a definite history of IVDU. TVE was associated with tricuspid regurgitation (TR) but TR severity did not correlate with worse outcome (p=0.238). Comorbidities included pulmonary septic emboli, heart failure (HF), pulmonary embolism, abscess, respiratory failure, cardiac arrest, and pneumonia. Staphylococcus aureus was the most common pathogen (57/80, 71.3%) with similar rates of MSSA and MRSA. Factors associated with in-hospital mortality included presence of prosthetic TV (p=0.005), prior diagnosis of HF (p=0.012), and MRSA infection (p=0.028). (Table 1) Medication-assisted treatment of opioid use disorder was associated with a lower rate of leaving the hospital against medical advice (p=0.006). Conclusions: Given the complexity of disease processes associated with TVE, a multidisciplinary approach to management is necessary. A prospective study following this vulnerable patient population in the inpatient and outpatient setting is warranted to further decrease the morbidity and mortality associated with this devastating disease.

To determine the resistance pattern of Staphylococcus aureus in pus samples

Staphylococcus aureus is a common health problem occuring as an important nosocomial pathogen, causing urinary tract infection, surgical site, blood stream and soft tissue infection. The aim of this research was conducted to determine MRSA and VRSA from the pus samples of admitted patients.The aim and objective of study was to isolate the resistance pattern of Staphylococcus aureus in pus samples and their AST. A total of 158 positive culture Staph aureus were taken from pus samples for the study during December 2019 - October 2020. Samples were cultured on Blood and MacConkey agar then incubated at 37C for 24 hours. The modified Kirby Bauer's disc diffusion method was used to test antibiotic sensitivity of staphylococcus isolates. In total of 158 positive culture of Staphylococcus aureus, 66 (41.7%) were found to be MRSA and 4 (2.5%) were found to be VRSA. Out of 158 Staph aureus, 146 (92.4%) were resistant to Penicillin, followed by Amoxycillin 140 (88.6%), Ampicillin 139 (87.9%), Erythromycin 91 (57.5%), Cefoxitin 66 (41.7%), Gentamycin 56 (35.4%), Amikacin 52 (32.9%) and Teicoplanin 37 (23.4%).: An antibiotic policy and screening of susceptibility patterns of MRSA may help in reducing the prevalence rate of MRSA and antibiotic resistance. To stop its spread to the population, it is very important to eliminate MRSA colonization in patients and health care workers. Accurate treatment helps to reduce the rate of morbidity and improvement of patient’s outcome.

The Distribution and Source of MRDOs Infection: A Retrospective Study in 8 ICUs, 2013-2019.

BackgroundTo analyze the distribution and source of MDROs infection in the ICUs and to provide a basis for formulating more effective prevention and control programs for MDROs.MethodsA retrospective investigation was conducted on MDROs infection in 8 ICUs of a large tertiary hospital from July 2013 to June 2019. A total of 2629 strains of MDROs isolated from 1701 inpatients were selected for analysis. The MDROs of the 8 ICUs were divided into two types of four categories according to source: out-of-hospital (out-of-hospital transfer and community acquisition) and in-hospital (in-hospital transfer and department acquisition) infections.ResultsCRAB (41.84%) and CRE (35.07%) accounted for the majority of the infecting MDROs. The detection rates of MRSA, CRAB, CRPA and CRE were 61.24%, 83.75%, 43.01% and 30.15%, respectively. The top three infection sites of MDROs were the lower respiratory tract (81.10%), blood (6.70%) and abdominal cavity (5.80%). The out-of-hospital and in-hospital infection rates of MDROs were 50.51% and 49.49%, respectively; the out-of-hospital infection rates for MRSA, CRAB, CRPA and CRE were 43.56%, 55.91, 64.44% and 44.58%, respectively. The proportions of MRSA, CRAB, CRPA and CRE infections contracted in the department were 40.98%, 36.27%, 25.56% and 46.62%, respectively. There was a statistically significant difference between comprehensive ICU and specialized ICU wards as sources for CRAB infections (P < 0.001).ConclusionThe main source of MDROs in the ICU is not the hospital itself entirely. It is particularly important to strengthen the identification of MDRO sources and implement more effective and accurate infection prevention and control measures.

Preparation of NIR-responsive, ROS-generating and antibacterial black phosphorus quantum dots for promoting the MRSA-infected wound healing in diabetic rats

Multidrug-resistant (MDR) bacteria-induced infection is becoming a huge challenge for clinical treatment, especially for non-healing diabetic wound infections, which increase patient mortality. MRSA infections and delayed wound healing (methicillin-resistant Staphylococcus aureus) accounted for a higher proportion. Although surgical debridement and continuous use of antibiotics are still the main clinical treatments, new multifunctional therapeutic nanoplatform are attractive for MIDW. Thus, in the present study, black phosphorus quantum dots (BPQDs) encapsulated in hydrogel (BPQDs@NH) were utilized as nanoplatforms for MIDW treatment to achieve the multifunctional properties of NIR (near infrared) responsiveness, ROS (reactive oxygen species) generation and antibacterial activity. Upon NIR irradiation, the temperature of the BPQDs@NH-treated MIDW area rapidly increased up to 55 °C for sterilization. In vitro experiments showed that BPQDs@NH exerted a synergistic effect on inhibiting MRSA by producing of ROS, lipid peroxidation, glutathione, adenosine triphosphate accumulation and bacterial membrane destruction upon NIR irradiation. The resulting BPQDs@NH achieved an effective sterilization rate of approximately 90% for MRSA. Furthermore, animal experiments revealed that BPQDs@NH achieved an effective closure rate of 95% for MIDW after 12 days by reducing the inflammatory response and regulating the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Meanwhile, intravenous circulation experiments showed good biocompatibility of BPQDs, and no obvious damage to rat major organs was observed. The obtained results indicated that BPQDs@NH achieved the synergistic functions of NIR-responsiveness, ROS generation, and antibacterial activity and promoted wound healing, suggesting that they are promising multifunctional nanoplatforms for MIDW healing. Statement of significance1. NIR-triggered ROS-generating and antibacterial nanoplatforms are attractive in the wound healing field. 2. In this work, black phosphorus quantum dots encapsulated in a hydrogel were used as a nanoplatform for treating MRSA infected wounds. 3. The obtained materials have achieved an effective sterilization rate for MRSA and effective wound closure rate.

Distribution of Common Pathogens and Bacterial Resistance in A Tertiary Hospital in China

We aimed to explore the distribution of common pathogens and bacterial resistance in our hospital from 2017 to 2020, and to standardize clinical medication guidance. The pathogens isolated from the submitted specimens were identified, and drug susceptibility results were interpreted according to the Clinical and Laboratory Standards Institute guidelines (2017-2020). A total of 43,588 specimens were collected from patients treatedfrom 2017 to 2020, and 6,285 strains of pathogens were isolated. The most common pathogens were Escherichia coli, Haemophilus influenzae and Klebsiella pneumoniae.Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 32.85%, and methicillin-resistant coagulase-negative Staphylococcus (MRCNS) accounted for 78.79%. The resistance rates of MRSA and MRCNS to ciprofloxacin, levofloxacin, erythromycin, clindamycin and trimethoprim-sulfamethoxazole were significantly higher than those of methicillin-sensitive S. aureus and methicillin-sensitive coagulase-negative Staphylococcus. The resistance rate of Streptococcus pneumoniae to erythromycin, tetracycline and clindamycin was higher than 80%. The detection rates of E. coli and K. pneumoniae producing ESBL strains were 62.2% and 25.6%, respectively. Totally, 769 carbapenem-resistant strains were detected, of which carbapenem-resistant Acinetobacter baumannii (CRAB) accounted for 66.6%, followed by carbapenem-resistant K. pneumoniae (CRKP) and carbapenem-resistant Pseudomonas aeruginosa (CRPA). A total of 202 CRE strains were detected, which were mainly isolated from respiratory tract and urine specimens. CRAB, CRKP and CRPA had higher resistance rates to antibacterial drugs. Gram-negative bacilli are the most common pathogens from 2017 to 2020. Considering that pathogens have high drug resistance, it is recommended to strengthen clinical management and rational application of antibiotics, thus reducing the risk of nosocomial infections.

Effect of ZnO nanoparticles on methicillin, vancomycin, linezolid resistance and biofilm formation in Staphylococcus aureus isolates

BackgroundMultidrug resistant (MDR) and biofilm producing Staphylococcus aureus strains are usually associated with serious infections. This study aimed to evaluate the antibacterial and antibiofilm-formation effects of zinc oxide nanoparticles (ZnO-NPs) against staphylococcus aureus (S. aureus) isolates.MethodsA total of 116 S. aureus isolates were recovered from 250 burn wound samples. The antimicrobial/antibiofilm effects of ZnO-NPs against methicillin, vancomycin and linezolid resistant S. aureus (MRSA, VRSA and LRSA) isolates were examined using phenotypic and genotypic methods. The minimum inhibitory concentration (MIC) of ZnO-NPs was determined by microdilution method. The effects of sub-MIC concentrations of ZnO-NPs on biofilm formation and drug resistance in S. aureus were determined by the microtiter plate method. The change in the expression levels of the biofilm encoding genes and resistance genes in S. aureus isolates after treatment with ZnO-NPs was assessed by real time reverse transcriptase PCR (rt-PCR).ResultsMICs of ZnO-NPs in S. aureus isolates were (128–2048 µg/ml). The sub-MIC of ZnO-NPs significantly reduced biofilm formation rate (the highest inhibition rate was 76.47% at 1024 µg/ml) and the expression levels of biofilm genes (ica A, ica D and fnb A) with P < 0.001. Moreover, Sub-MIC of ZnO-NPs significantly reduced the rates of MRSA from 81.9 (95 isolates) to 13.30% (15 isolates), VRSA from 33.60 (39 isolates) to 0% and LARSA from 29.30 (34) to 0% as well as the expression levels of resistance genes (mec A, van A and cfr) with P value < 0.001.ConclusionZnO-NPs can be used as antibiofilm and potent antimicrobial against MRSA, VRSA and LRSA isolates.

Community-acquired bacteremia among HIV-infected and HIV-exposed uninfected children hospitalized with fever in Mozambique

Background:Bacteremia is a major cause of morbidity and mortality worldwide. Children infected with HIV present with patterns of bacteremia generally associated with poor prognosis. In Mozambique, data on bacteremia are sparce.Methods:We conducted an observational study of HIV-infected and HIV-exposed uninfected children, aged 0–59 months, hospitalized with fever between April 1, 2016 and February 28, 2019. A single bacterial culture was collected at admission. Descriptive statistics were used to summarize microorganisms detected and antibiotic susceptibility testing.Results:A total of 808 HIV-infected (90%) and HIV-exposed uninfected (10%) children were enrolled. Blood culture positivity was 12% (95% CI: 9.9%–14.4%). Five organisms accounted for most cases: Staphylococcus Aureus (37%), Klebsiella spp (11%), Salmonella spp (11%), Escherichia Coli (9%) and Micrococcus (7%). Antibiotic resistance was common. Nearly 70% of Staphylococcus Aureus were methicillin-resistant and roughly 50% of Klebsiella had ESBL production.Conclusion:Community-acquired bacteremia was common in HIV-infected and HIV-exposed uninfected children hospitalized in Mozambique with a febrile illness. High rates of MRSA and ESBL producing organisms has implications for empiric antibiotics utilized in Mozambique. Longitudinal data on the prevalence and antimicrobial resistance patterns of important pathogens are badly needed to guide policy for drug formulary expansion and antibiotic prescription guidelines.

Phenotypic and Genotypic Detection of Methicillin Resistant Staphylococcus aureus in Health Care Workers and Its Containment in a Tertiary Care Hospital, in South India

MRSA causes nosocomial and community based infections. It is associated with significant mortality and morbidity. Resistance in MRSA is encoded by mecA gene. Anterior nares are the ecological niche of Staphylococcus aureus. HCWs who are colonized with MRSA, act as agents of cross contamination of hospital and community acquired MRSA. Treating MRSA infections is a therapeutic challenge as it is resistant to beta lactam group of drugs. Therefore, there is a need for rapid and accurate detection of MRSA carriage in HCWs and to understand its antibiotic susceptibility pattern.The objective of the present study is to estimate the occurrence of MRSA in HCWs, using phenotypic and genotypic methods. A prospective study for six months was conducted after obtaining Institutional Ethical Committee clearance. Anterior nasal swabs of those HCWs who gave informed consent were taken processed for culture and sensitivity as per standard protocol. To detect MIC for oxacillin, E-strip method was used. mecA gene detection was done by PCR. A total of 300 HCWs were sampled.14.66% (44/300) of the isolates were identified as Staphylococcus aureus, of which 10 isolates were detected as MRSA. The overall isolation rate of MRSA is 3.33 %(10/300). MRSA carriage was high amongst nurses (5/59, 8.47%), followed by doctors (4/105, 3.80%).Antibiotic sensitivity pattern showed that highest resistance was to penicillin (75%) followed by amoxiclav (70.45 %).9 MRSA isolates were detected as mecA gene positive by PCR. MRSA carriers were decontaminated successfully with 2% mupirocin ointment and 2% chlorhexidine shampoo. This study reiterates the need for rapid and accurate identification of HCWs who have nasal colonization with MRSA, for reinforcing hospital infection control measures and decontamination protocol. This will help prevent the spread of MRSA in our community.

Clonal diversity and spatial dissemination of multi-antibiotics resistant Staphylococcus aureus pathotypes in Southwest Nigeria

Spread of genetically diverse Staphylococcus aureus characterized with multi-antibiotic resistance and regulated by high level agr functionalities in several communities in southwest Nigeria was investigated and evaluated for infection control. Staphylococcus aureus pathotypes recovered from 256 cases including purulent pus from skin infections, soft tissue aspirates, wounds, otorrhea, eye, throat and endocervical infections were assayed for biofilm and antibiogram. Further genotyped with micro-array, mapped for geospatial distribution and evaluated for clonal diversity and functional accessory gene regulators (agr). Significant Staphylococci infection among the ages (OR:0.021, CI:0.545–1.914) and female gender with prevalence rate of MSSA (53.0%) and MRSA (1.5%) (OR:1.021, CI:0.374–1.785) were observed. More than 52.5% resistance rates to tetracycline and amoxicillin with significant median resistance were observed in all the infection cases (p = 0.001). Resistance rate of 78.8% at MIC50 32μg/ml and MIC90 128μg/ml to amoxicillin-clavulanate, and more than 40% resistance to ceftazidime, ciprofloxacin and tetracycline of MIC90 and MIC50 at 32 μg/ml were observed. Strains with multi-antibiotic resistance index above 0.83, high beta-lactamase and strong biofilm clustered into separate phylo-group. Heterogeneous t442 (wound and pus), t657 (wound), t091 (ear) and t657 (ear and wound) revealed high phylogenetic diversity. Only 4.6% pvl+ MSSA-CC1 agrI, pvl+ MSSA-CC5 (13.6%) and pvl+ MRSA-CC7 agrII (4.6%), expressed enterotoxin, leukocidins, proteases and resistance gene determinants. Livestock clonal types clustered with identified community-associated strains. Clonal dissemination of resistant pvl+ MSSA-CC1 and MRSA-CC5 encoding agr were predominant in several peri-urban communities where adequate geno-surveillance, population-target antimicrobial stewardship, extensive community structured infection control programs are needed to prevent further focal dissemination.

Staphylococcus aureus’un Onbeş Yılda Metisilin Direnç ve Antibiyogram Direnç Profilinin ve Görülme Sıklığının Değişimi

Objective: The aim of this retrospective study was to evaluate the rate and antimicrobial resistance profile of community-acquired (CA) and hospital-acquired (HA) methicillin-resistant and sensitive Staphylococcus aureus (MRSA, MSSA) strains between 2004 and 2019. Method: Within the scope of the research, the rate of MRSA and MSSA and the change in antimicrobial resistance profile over time were investigated using two research data of 210 Staphylococcus aureus strains isolated in 2004, and 401 in 2019. Results: While any significant change was not seen in the rates of CA-MRSA (32.4%) and CA-MSSA (67.6%) in 2004, and of CA-MRSA (31.6%) and CA-MSSA (68.4%) in 2019, the prevalence of HA-MRSA decreased by 56.1% in 2004 and 30.7% in 2019 and of HA-MSSA increased by 43.9% in 2004 and 69.3% in 2019. No resistance to vancomycin and teikoplanin was observed in MRSA strains. Resistance of CA-MRSA against ciprofloxacin, levofloxacin, clindamycin and gentamicin decreased. In CA-MSSA an increase of penicillin resistance as well as a decrease in gentamicin resistance was observed. In resistance of HA-MRSA against ciprofloxacin, levofloxacin, erythromycin, clindamycin, gentamicin decreased. HA-Resistance of MSSA against fusidic acid increased and against ciprofloxacin and trimethoprim/sulfamethoxazole and erythromycin resistance decreased. Conclusion: It was found that the rate of HA-MRSA decreased during the given period of 15 years. Vancomycin or teicoplanin resistance was not observed in MRSA and MSSA. While against ciprofloxacin, levofloxacin, clindamycin, gentamicin decreased in both CA-MRSA and HA-MRSA. A closer follow-up of the prevalence and antimicrobial resistance profiles of these strains is of utmost importance for the successful control of the infections caused by MRSA and MSSA.

Correlation Between Methicillin Resistance and Enterotoxins Production in Staphylococcus aureus Isolated from some Salted Fish

The goal of this research was to find out Staphylococcus aureus incidence in sixty samples of some salted fish (salted sardine, Feseikh, and Molouha) obtained from random places in Kafrelsheikh Governorate as well as the prevalence rate of MRSA (mecA gene) in relation to enterotoxin production (Sea, Seb, Sec, Sed) by using PCR techniques. Furthermore, studying the relationship between salt content and the occurrence of Staph. aureus. Overall, coagulase positive Staph. aureus was identified in 30, 20, and 10% of salted sardine, feseikh, and molouha samples, with mean values of 3.05± 1.73, 3.45± 2.14 and 2.64± 1.39 (log 10) cfu/g, respectively. The mec A gene was identified by PCR in all coagulase positive Staph. aureus isolates (12 isolate), otherwise Sea gene wasn't detected in any of the positive MRSA isolates, Seb and Sec genes were found in 33.33% (each) of MRSA strains from salted sardine samples and 25% (each) of MRSA isolates from feseikh samples, and only one isolate (50%) from the molouha samples contained Sed gene. The salt content of the examined molouha samples were noticeably different (P< 0.05) from the other examined samples, whereas, between salted sardine and feseikh samples there was no statistically significant difference (P< 0.05), and inverse relationship was found between salt content and the prevalence of Staph. aureus. The presence of MRSA with staphylococcal enterotoxigenic genes in salted fish could be regarded as providing a health risk to consumers. Therefore, a significant effort should be made to maintain hygienic conditions in the processing, preparation, and handling of fish products to keep contamination to a minimum.

257. Staphylococcus aureus Bacteremia: Does Intravenous Drug Use Impact Quality of Care and Clinical Outcomes?

BackgroundIndividuals with intravenous drug use (IDU) have higher risk for Staphylococcus aureus bacteremia (SAB) and increased management complexity. The goal of this study was to compare differences in SAB characteristics, adherence to standard of care metrics, and clinical outcomes in those with and without IDU.MethodsA retrospective chart review was conducted on cases of SAB between January 1, 2016 and December 31, 2017 at a 500-bed teaching hospital. Inclusion criteria was age > 18 years and ≥ one blood culture positive for S. aureus. Patients were excluded if they transferred hospitals, had care withdrawn or died within 48 hours of diagnosis or had a ventricular assist device infection. Records were reviewed for substance use, SAB characteristics, standards of care, and outcomes. Data were analyzed using SPSS software. The study was approved by the Institutional Review Board.ResultsIn 248 patients with SAB, 28.2% had documented IDU. Median age was 37 (IDU) and 57 (non-IDU). In the IDU group, 75.7% had the formal diagnosis of opioid use disorder and 78.9% of stimulant use disorder. IDU was associated with hepatitis C and houselessness while non-IDU was associated with diabetes, hemodialysis, and cancer. Those with IDU had higher rates of MRSA, endocarditis, and spinal infections, but did not have higher rates of polymicrobial infections or venous thrombosis. There was no difference in appropriate repeat blood cultures, antibiotic management, and ID consultation. Length of stay and against medical advice (AMA) discharges were higher in those with IDU. There was no difference in 90-day recurrence or readmission, but 90-day mortality was higher in the non-IDU group. ConclusionThere was no difference in adherence to SAB quality of care metrics between groups with and without IDU. Despite the IDU group being younger with fewer comorbidities, 90-day readmissions were not different between groups. This bears further analysis but may represent the influence of therapy completion, AMA discharges, and unmeasured social determinants of health.Disclosures All Authors: No reported disclosures

865. Methicillin-resistant Staphylococcus aureus (MRSA) prevalence among healthcare workers (HCW) in contact tracings in a Dutch teaching hospital, 2010-2018

BackgroundIn The Netherlands, the national guidelines on MRSA prevention and control advocate screening of HCW after unprotected exposure to MRSA carriers. Although this strategy at large is successful, contact tracing of staff is a time consuming and costly component. We evaluated our contact tracing policy for HCW over the years 2010 – 2018.MRSA prevalence among samples in contact tracing MethodsA retrospective, observational study was performed in a Dutch teaching hospital. All HCW who had unprotected contact with an MRSA carrier were included in contact tracing. When there had been a long period of unprotected admission prior to an MRSA finding, or when the index case was a HCW, than the entire (nursing) team was tested. All samples of HCWs who were tested for MRSA carriage as part of contact tracing from 2010 until 2018 were included. A pooled nose, throat and perineum swab was collected using the eSwab medium (Copan) and inoculated on chromID MRSA agar plates (bioMérieux) after enrichment in a broth.ResultsIn total, we included 8,849 samples (range: 677 – 1,448 samples per year) from a total of 287 contact tracings (range: 26 – 55 contact tracings per year). Thirty two HCWs were colonized with MRSA (0.36%; 95%CI 0.26 – 0.51). None of them developed a clinical infection.Eight HCWs (0.10%; 95%CI 0.05% – 0.19%) were colonized with the same MLVA type as the index case, and were detected in 6/287 contact tracings (2%). In 4/8 of these cases, a positive HCW was the index for undertaking contact tracing. In 3/8 cases it was clear that the HCW who was identified in the contact tracing was the source of the outbreak and was the cause of invasive MRSA infections in patients.Notably, a different MLVA type as the index case was found in 24 HCWs (0,27%; 95%CI 0,18 – 0,40) of which 7/24 HCW (29,2%) were intermittent carriers.ConclusionThis study revealed a sustained low MRSA prevalence among samples in contact tracing of healthcare workers, over nine years. Furthermore, it shows that when MRSA contact tracing is performed according to the national guideline only 1 out 1000 samples results in a secondary case. This is similar to the population carriage rate of MRSA in The Netherlands. More frequently, an unrelated strain is found. These findings raise question marks regarding the efficacy of the current strategy to perform contact tracing after unprotected exposure.Disclosures All Authors: No reported disclosures

Occurence and Antimicrobial Resistant Patterns of Methicillin Resistant Staphylococcus Aureus (MRSA) Among Practicing Veterinarians in Kebbi State, Nigeria

Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging zoonotic pathogen incriminated in causing multiple disease conditions in humans and livestock. Studies have shown relationships between livestock rearing and increased MRSA colonization risk among farm workers, and also suggest that livestock may serves as reservoirs of the bacteria and could also infect humans via close contact and consumption of contaminated animal products. The aim of this study was to investigate if practicing veterinarians with significant livestock contacts are at risk for MRSA colonization. Therefore, a non-randomized survey was conducted to establish the presence of MRSA among veterinarians practicing in Kebbi State Nigeria, using both cultural characteristics and molecular detection of the resistant gene (mecA). Forty-one (41) nasal swabs were aseptically collected. The detection rate of MRSA in the veterinarians was 14.6 %. The study revealed a high occurrence rate of MRSA among veterinarians in the study area. The relatively high prevalence recorded among veterinarians in this study could be attributed to the poor understanding of MRSA as a disease, its mode of transmission and its status in the country which have contributed immensely to the little/no awareness of MRSA among veterinarians and hence making it favourable for the bacteria (MRSA) to spread.

Validation of Administrative Codes for Identification of Staphylococcus aureus Infections Among Electronic Health Data

Background: Epidemiological studies have utilized administrative discharge diagnosis codes to identify methicillin-resistant and methicillin-sensitive Staphylococcus aureus (MRSA and MSSA) infections and trends, despite debate regarding the accuracy of utilizing codes for this purpose. We assessed the sensitivity and positive predictive value (PPV) of MRSA- and MSSA-specific diagnosis codes, trends, characteristics, and outcomes of S. aureus hospitalizations by method of identification. Methods: Clinical micro biology results and discharge data from geographically diverse US hospitals participating in the Premier Healthcare Database from 2012–2017 were used to identify monthly rates of MRSA and MSSA. Positive MRSA or MSSA clinical cultures and/or a MRSA- or MSSA-specific International Classification of Diseases, Ninth/Tenth Revision, Clinical Modification (ICD-9/10 CM) diagnosis codes from adult inpatients (aged ≥18 years) were included as S. aureus hospitalizations. Septicemia was defined as a positive blood culture or a MRSA or MSSA septicemia code. Sensitivity and PPV for codes were calculated for hospitalizations where admission status was not listed as transfer; true infection was considered a positive clinical culture. Negative binominal regression models measured trends in rates of MRSA and MSSA per 1,000 hospital discharges. Results: We identified 168,634 MRSA and 148,776 MSSA hospitalizations in 256 hospitals; 17% of MRSA and 21% of MSSA were septicemia. Less than half of all S. aureus hospitalizations (49% MRSA, 46% MSSA) and S. aureus septicemia hospitalizations (37% MRSA, 38% MSSA) had both a positive culture and diagnosis code (Fig. 1). Sensitivity of MRSA codes in identifying positive cultures was 61% overall and 56% for septicemia, PPV was 62% overall and 53% for septicemia. MSSA codes had a sensitivity of 49% in identifying MSSA cultures and 52% for MSSA septicemia; PPV was 69% overall and 62% for septicemia. Despite low sensitivity, MRSA trends are similar for cultures and codes, and MSSA trends are divergent (Fig. 2). For hospitalizations with septicemia, mortality was highest among those with a blood culture only (31.3%) compared to hospitalizations with both a septicemia code and blood culture (16.6%), and septicemia code only (14.7%). Conclusions: ICD diagnosis code sensitivity and PPV for identifying infections were consistently poor in recent years. Less than half of hospitalizations have concordant microbiology laboratory results and diagnosis codes. Rates and trend estimates for MSSA differ by method of identification. Using diagnosis codes to identify S. aureus infections may not be appropriate for descriptive epidemiology or assessing trends due to significant misclassification.Funding: NoneDisclosures: Scott Fridkin reports that his spouse receives consulting fees from the vaccine industry.

Clinical and Financial Implications for Discontinuing Active Surveillance Culturing (ASC) for Methicillin-resistant Staphylococcus Aureus & Vancomycin-resistant Enterococcus in Community Hospitals

Background Active surveillance culturing (ASC) is widely used to prevent the spread of select multi-drug resistant organisms. As infection prevalence changes over time, the value and effectiveness of ACS requires periodic re-assessment. The two primary objectives of this study were to determine whether discontinuation of ASC for MRSA and VRE was associated with any increased incidence of hospital-acquired MRSA or VRE infection, and to estimate the financial impact of discontinuing MRSA and VRE ASC. Methods Rates of hospital-acquired (HA) infection or colonization with MRSA & VRE (excluding screening tests) were compared before and after discontinuation of VRE ASC and limitation of MRSA ASC in two separate community hospitals in eastern North Carolina between 2016 and 2019. Financial costs were estimated from direct laboratory costs and personal protective equipment (PPE) use pre- and post-elimination of ASC. Results HA-VRE rates were similar between sites and showed no significant difference following discontinuation of VRE ASC (risk ratio 0.79, 95% CI: 0.24-2.52, p=0.69). HA-MRSA rates were more difficult to interpret as rates differed between sites, and one site only had 2 months of data available following ASC limitation. Despite these limitations, within-site MRSA rates showed no significant change before or after limitation of MRSA ASC. Aggregate HA-MRSA rates actually fell slightly following limitation of MRSA ASC (risk ratio 0.40, 95% CI 0.18-0.91, p=0.04). Complete cost data for PPE usage was available for facility A and complete laboratory cost data for facility B. Both showed significant reductions after limiting ASC (p<0.001). Conclusions Rates of MRSA and VRE infection/colonization were overall low, but showed no significant change following discontinuation of ASC at two separate community hospitals. The discontinuation of ASC lead to cost savings for both facilities with no increased harm observed. Active surveillance culturing (ASC) is widely used to prevent the spread of select multi-drug resistant organisms. As infection prevalence changes over time, the value and effectiveness of ACS requires periodic re-assessment. The two primary objectives of this study were to determine whether discontinuation of ASC for MRSA and VRE was associated with any increased incidence of hospital-acquired MRSA or VRE infection, and to estimate the financial impact of discontinuing MRSA and VRE ASC. Rates of hospital-acquired (HA) infection or colonization with MRSA & VRE (excluding screening tests) were compared before and after discontinuation of VRE ASC and limitation of MRSA ASC in two separate community hospitals in eastern North Carolina between 2016 and 2019. Financial costs were estimated from direct laboratory costs and personal protective equipment (PPE) use pre- and post-elimination of ASC. HA-VRE rates were similar between sites and showed no significant difference following discontinuation of VRE ASC (risk ratio 0.79, 95% CI: 0.24-2.52, p=0.69). HA-MRSA rates were more difficult to interpret as rates differed between sites, and one site only had 2 months of data available following ASC limitation. Despite these limitations, within-site MRSA rates showed no significant change before or after limitation of MRSA ASC. Aggregate HA-MRSA rates actually fell slightly following limitation of MRSA ASC (risk ratio 0.40, 95% CI 0.18-0.91, p=0.04). Complete cost data for PPE usage was available for facility A and complete laboratory cost data for facility B. Both showed significant reductions after limiting ASC (p<0.001). Rates of MRSA and VRE infection/colonization were overall low, but showed no significant change following discontinuation of ASC at two separate community hospitals. The discontinuation of ASC lead to cost savings for both facilities with no increased harm observed.

Vancomycin and linezolid resistance among multidrug-resistant Staphylococcus aureus clinical isolates and interaction with neutrophils

BackgroundDeveloped drug resistance against vancomycin and linezolid is a huge worrisome. The aim of our study was to investigate the rate of vancomycin and linezolid resistance in multidrug-resistant (MDR) Staphylococcus aureus (S. aureus) in Baghdad, Iraq. MethodsThree-hundred S. aureus were identified from various clinical origins in Baghdad, Iraq. Methicillin-and linezolid-resistant S. aureus (MRSA and LRSA, respectively) isolates were determined by disc diffusion, agar dilution and E-test methods. Biofilm formation was assayed using microtiter tissue plate (Mtp) assay. Polymerase chain reaction (PCR) was employed to detect the mecA, vanA, B, C, cfr and adhesin genes, followed by gene sequencing. Vancomycin-resistant S. aureus (VRSA) and LRSA strains interactions with neutrophils was assessed using flow-cytometry technique. ResultsTwo-hundred (67%) isolates were MRSA. One-hundred one (50.5%) and 44 (22%) MRSA were strong and moderate-level biofilm producers, respectively. All the strong biofilm-producer MRSA carried the clfA, clfB, fnbA, fnbB, fib and eno genes. Five (1.66%) and nine (3%) of the MRSA were VRSA and LRSA, respectively which were mostly isolated from blood and tissue infections. The vanA and cfr genes were detected in two and three MRSA, respectively. Three VRSA and two LRSA strains were strong biofilm-producers and contained adhesin genes (clfA, clfB, fnbA, fnbB, eno, fib, cna and ebps, but not bbp). The neutrophils mean apoptosis rate by the VRSA and LRSA strains included 80% and 66.7%, respectively. ConclusionVirulent MRSA rate was high. In addition, MRSA, VRSA and LRSA contained adhesin genes responsible for colonization and biofilm formation. Furthermore, these strains induced the neutrophils apoptosis. The evolution of pathogenic VRSA and LRSA is a concern towards eradication of MDR-S. aureus. More detailed works will be helpful to disclose the role of bacterial components in the biofilm formation and apoptosis and control strategies.

Current status of Panton-Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus isolated from patients with skin and soft tissue infections in Japan.

The USA300 clone, which produces Panton-Valentine leukocidin (PVL), is a major pathogenic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone that causes intractable skin infections. Recently, PVL-positive CA-MRSA, including USA300 clones, have emerged in both communities and hospitals in Japan. To prevent an outbreak of PVL-positive MRSA, infected patients should be treated with effective antimicrobial agents at community clinics. Herein, we investigate molecular epidemiological characteristics of PVL-positive MRSA isolated from outpatients with skin and soft tissue infections (SSTI), which are common community-onset infectious diseases. The detection rate of MRSA was 24.9% (362 strains) out of 1455 S.aureus strains isolated between 2013 and 2017. Among the MRSA strains, 15.5% (56 strains) were PVL-positive strains and associated with deep-seated skin infections. Molecular epidemiological analyses of PVL-positive MRSA showed that USA300 was the predominant clone (53.6%, 30 strains) and was identified in Kanto (18 strains), Kagawa (nine strains), Tohoku (two strains) and Hokkaido (one strain). Notably, minocycline and fusidic acid were effective against all PVL-positive MRSA strains. Hence, our data reveals the current status of PVL-positive MRSA isolated from patients with SSTI in Japan. Continuous surveillance of CA-MRSA is necessary to monitor latest prevalence rates and identify effective antimicrobial agents for PVL-positive MRSA strains.