Methicillin-resistant S. Aureus Rates Research Articles

Occurrence of high level methicillin resistance Staphylococcus aureus in patients from health facilities in Akwa Ibom State, Nigeria

Background: Methicillin resistant S. aureus (MRSA) has become a major public health predicament worldwide. This is owing to its involvement in the evolution of MDR strains and difficulty in therapeutic management of infected patients. This study was conducted to investigate the prevalence of methicillin resistance Staphylococcus aureus among patients in two health facilities in Akwa Ibom State, Nigeria. Materials and Methods: Clinical isolates of patients from University of Uyo Teaching Hospital (UUTH), Uyo and General Hospital, Ikot Abasi (GHIA) were investigated based on the strategic location of the hospitals. The study design was a descriptive cross-sectional study. Three hundred clinical samples were collected from male and female in and out-patients of all ages and processed using standard bacteriological methods. Detection of Staphylococcus aureus and MRSA strains were done according to standard protocols while antibiotic susceptibility testing of MRSA isolates was conducted using Kirby-Bauer disc diffusion method and interpreted following the CLSI 2021 guidelines. Results: The prevalence of MRSA strains in this study was 42.9%. Majority of patients with MRSA were from UUTH (44%) closely followed by patients from GHIA (40%). High antibiotics resistant rates of MRSA were recorded for ampicillin (96.6%), ciprofloxacin (73.3%), erythromycin (63.3%) and cotrimoxazole (60%). Gentamicin and ceftriaxone sensitivity rates were 53.3% and 63.4%, respectively. Conclusion: Health facilities in the state should institute effective antimicrobial stewardship, intensify surveillance and screening of Staphylococcus aureus for MRSA strains to guard against dissemination of multidrug resistant strains in both hospital and community settings because of the clinical implications.

Assessing Tetracycline susceptibility in multidrug-resistant Staphylococcus aureus: A clinical study in Kathmandu

Introduction: Staphylococcus aureus, recognized as an opportunistic pathogen, is frequently implicated in diverse human infections. Managing multidrug-resistant S. aureus poses a significant challenge in the clinical sector. Beyond B-lactam antibiotics, healthcare practitioners commonly prescribe Glycopeptides, Tetracycline, Quinolones, and Macrolide-Lincosamide-Streptogramin B antibiotics as alternative treatments for such infections. Consequently, this study was undertaken to evaluate the susceptibility of multidrug-resistant S. aureus to tetracycline in clinical samples. Methods: The study spanned 15 months, from March 2020 to May 2021, during which clinical samples were collected from three distinct hospitals in Kathmandu-Dirghayu Guru Hospital, Chabahil; Bhaktapur Cancer Hospital, Bhaktapur; and Shankarapur Hospital, Jorpati. Sample processing and laboratory work were conducted in the Microbiology Laboratory of Dirghyau Guru Hospital to assess the prevalence of different multidrug-resistant (MDR) phenotypes among S. aureus and their correlation with Methicillin resistance. The study included 266 isolates of S. aureus, and Methicillin resistance was determined using the Cefoxitin disc diffusion method. Results: Among 2004 clinical samples processed, 266 (13.27%) isolates were S. aureus. The multidrug resistant strain isolated from Outpatient department was 56.84% (54/95) and from inpatient department, the data was 43.15% (41/95). Among the 266 S. aureus, 28.94% Methicillin resistant S. aureus (MRSA) and 71.05% Methicillin sensitive S. aureus (MSSA) isolates were detected. Tetracycline resistance was found in 9.8% of total S. aureus isolates whereas 27.36% (26/95) among multidrug resistant S. aureus isolates. Resistance to Tetracycline was higher in MRSA as compared to MSSA. Conclusion: The detection rate of MRSA emphasizes the urgency to improve healthcare practices to control the spread of MRSA infections. Tetracycline can be used as a viable alternative antibiotic for combating S. aureus infections, particularly in Kathmandu.

The occurrence and contamination of optrA-positive methicillin-resistant Staphylococcus aureus from duck farms in Guangdong, China

Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), is an important zoonotic microorganism that increasingly causes public health concern worldwide. The objective of this study was to determine the prevalence and transmission of S. aureus in duck farms and evaluate its antimicrobial resistance and genetic characteristics. The samples associated with ducks, feeders, and the environment were collected on 14 duck farms from four areas in Guangdong, China, from 2020 to 2021. All isolates were subjected to antimicrobial susceptibility testing. A comprehensive epidemiological survey of S. aureus was conducted by S. aureus protein A typing and whole-genome sequencing. A total of 560 samples were collected. The prevalence rate of MRSA among ducks (8.1%, 11 of 135) was higher compared with that in environmental samples. OptrA-positive ST398-t034 MRSA were first detected from duck farms in China. A total of 79.3% (34 of 46) S. aureus isolates showed multidrug-resistant phenotypes. Notably, some isolates carried multidrug-resistant genes encoding macrolide-lincosamide-streptogramin B, pleuromutilin-pleuromutilin-streptogramin A, and oxazolidinone. Analysis of the virulence genes revealed that the MRSA isolates carried genes encoding gamma-hemolysin, enterotoxin, and leukocidin. ST9-t899 is a primary clonal lineage among duck- and environment-associated MRSA. Single-nucleotide polymorphism analysis showed the potential contamination relationship of optrA-positive ST2308 MRSA isolates carrying the gamma-hemolysin genes and the leukocidin virulence genes between airborne dust and sick ducks. The contamination of MRSA, especially optrA-positive MRSA, between food animals and the environment is a growing public health concern worldwide. Based on One Health principles, continuous surveillance of MRSA is urgently needed.

Machine learning to predict risk for community-onset Staphylococcus aureus infections in children living in southeastern United States.

Staphylococcus aureus (S. aureus) is known to cause human infections and since the late 1990s, community-onset antibiotic resistant infections (methicillin resistant S. aureus (MRSA)) continue to cause significant infections in the United States. Skin and soft tissue infections (SSTIs) still account for the majority of these in the outpatient setting. Machine learning can predict the location-based risks for community-level S. aureus infections. Multi-year (2002-2016) electronic health records of children <19 years old with S. aureus infections were queried for patient level data for demographic, clinical, and laboratory information. Area level data (Block group) was abstracted from U.S. Census data. A machine learning ecological niche model, maximum entropy (MaxEnt), was applied to assess model performance of specific place-based factors (determined a priori) associated with S. aureus infections; analyses were structured to compare methicillin resistant (MRSA) against methicillin sensitive S. aureus (MSSA) infections. Differences in rates of MRSA and MSSA infections were determined by comparing those which occurred in the early phase (2002-2005) and those in the later phase (2006-2016). Multi-level modeling was applied to identify risks factors for S. aureus infections. Among 16,124 unique patients with community-onset MRSA and MSSA, majority occurred in the most densely populated neighborhoods of Atlanta's metropolitan area. MaxEnt model performance showed the training AUC ranged from 0.771 to 0.824, while the testing AUC ranged from 0.769 to 0.839. Population density was the area variable which contributed the most in predicting S. aureus disease (stratified by CO-MRSA and CO-MSSA) across early and late periods. Race contributed more to CO-MRSA prediction models during the early and late periods than for CO-MSSA. Machine learning accurately predicts which densely populated areas are at highest and lowest risk for community-onset S. aureus infections over a 14-year time span.

Knowledge, Practices, and Nasal Carriage Rate of MRSA Amongst Dental Professionals

Resistance of Staphylococcus aureus (S. aureus) against common antibiotics has been increasing given the rampant use of antibiotics. Methicillin-resistant S. aureus (MRSA) is particularly important because it has been reported to present in hospital-acquired as well as community-acquired infections. Our aim was to study the types and subtypes of MRSA isolated from nasal swabs taken from volunteering dental school students and to assess and analyse the knowledge of dental health care workers (DHCWs) on MRSA and prevention of its infection. A total of 100 participants, which included staff, students, and dental auxiliaries, from the School of Dental Sciences, Krishna Institute of Medical Sciences, Deemed to Be University, Karad, India, were included in the study which was conducted from June 2020 to 1 June 2021. All the participants completed a survey and underwent collection of nasal swabs. The samples were cultured and underwent microbiological and molecular analysis for MRSA. The questionnaire was sent out electronically via SurveyMonkey. Sixty-three percent of the participants were female. The majority were undergraduate students (66%) and younger than 25 years (77%). The prevalence of MRSA in the sample was the MRSA type SCCmec type V (54.8%). The survey reports a lack of knowledge amongst dental students on MRSA and prevention of its infection. The majority (69%) of participants had not heard of MRSA infection and had inadequate knowledge of MRSA infection. Only 29% of the participants think that a healthy person may have MRSA without feeling ill. Eighty-five percent of the participants reported that they have written polices and guidelines to control MRSA. Eighty-five percent of the participants indicated that they are less confident in their knowledge on MRSA infection control protocols, and 94% mentioned that the dental clinics have written guidelines for hand hygiene. DHCWs have limited knowledge of MRSA infection, emphasising the need for appropriate clinical training. Academic institutions should promote effective infection control training to protect students, faculty, and other employees.

Development of a multiyear pediatric antibiogram in Georgia identifies antibiotic resistance trends

Background: Antibiograms are used to monitor antibiotic resistance trends and help guide empiric antibiotic treatment. Community pediatricians may not have access to or be comfortable using children’s hospital antibiograms. Creating and disseminating a statewide pediatric antibiogram can help inform antibiotic stewardship efforts.Objective: To develop a pediatric-specific antibiogram for the state of Georgia. Methods: Annual pediatric antibiograms for the 5 children’s hospitals in Georgia from 2014 through 2021 were collected. All sites complied with the Clinical and Laboratory Standards Institute guidelines for antibiomicrobic breakpoints and antibiogram development. Antibiogram data were combined, and the most common bacteria were selected to incorporate into the statewide antibiogram: Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae complex, and Pseudomonas aeruginosa. Antibiogram data were reported as percentage susceptible and total number of isolates. Interhospital susceptibility differences were compared for methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), E. coli, and K. pneumoniae from 2018 through 2021. P &lt; .05 was considered significant. The combined antibiogram data from 2014 through 2021 were used to show antibiotic susceptibility trends over time. Results: The 2021 antibiogram is shown in the Table. For MSSA and MRSA, clindamycin susceptibility was 80% and 85%, respectively. K. pneumoniae susceptibility to amoxicillin-clavulanate was 91%. For E. coli, using urine-specific breakpoints, susceptibility to cefazolin was 89%. A few statistically significant differences in antibiotic susceptibility were detected between hospitals, but most were unlikely to be clinically relevant (all susceptibilities ≥90% or &lt; 80%). A notable exception was trimethoprim-sulfamethoxazole susceptibility for K. pneumoniae, which ranged from 74% to 98% in 2020 and from 74% to 86% in 2021. From 2014 to 2021, the percentage of MRSA decreased from 49% to 34%. Over the 8 years, susceptibility to ceftriaxone for E. coli ranged from 93% to 95% and from 90% to 95% for K. pneumoniae. Susceptibility to meropenem for E. coli and K. pneumoniae ranged from 99% to 100%. Conclusions: Antibiotic susceptibility for pediatric bacterial isolates in Georgia remained stable over time and supported the narrow-spectrum empiric antibiotic treatment recommended in national evidence-based guidelines for skin and soft-tissue infections, community-acquired pneumonia, and uncomplicated urinary tract infections. MRSA rates decreased over time and multidrug-resistant gram-negative bacilli were uncommon and remained stable.Disclosures: None

Staphylococcus aureus bloodstream infection in a Chinese tertiary-care hospital: A single-center retrospective study.

Staphylococcus aureus bloodstream infection in a Chinese tertiary-care hospital: A single-center retrospective study.

Molecular and Source-Specific Profiling of Hospital Staphylococcus aureus Reveal Dominance of Skin Infection and Age-Specific Selections in Pediatrics and Geriatrics.

Staphylococcus aureus is a major human-associated pathogen that causes a wide range of clinical infections. However, the increased human dynamics and the changing epidemiology of the species have made it imperative to understand the population structure of local ecotypes, their transmission dynamics, and the emergence of new strains. Since the previous methicillin-resistant S. aureus (MRSA) pandemic, there has been a steady increase in global healthcare-associated infections involving cutaneous and soft tissue and resulting in high morbidities and mortalities. Limited data and paucity of high-quality evidence exist for many key clinical questions about the pattern of S. aureus infections. Using clinical, molecular, and epidemiological characterizations of isolates, hospital data on age and infection sites, as well as antibiograms, we have investigated profiles of circulating S. aureus types and infection patterns. We showed that age-specific profiling in both intensive care unit (ICU) and non-ICU revealed highest infection rates (94.7%) in senior-patients > 50 years; most of which were MRSA (81.99%). However, specific distributions of geriatric MRSA and MSSA rates were 46.5% and 4.6% in ICU and 35.48% and 8.065% in non-ICU, respectively. Intriguingly, the age groups 0−20 years showed uniquely similar MRSA patterns in ICU and non-ICU patients (13.9% and 9.7%, respectively) and MSSA in ICU (11.6%). The similar frequencies of both lineages in youth at both settings is consistent with their increased socializations and gathering strongly implying carriage and potential evolutionary replacement of MSSA by MRSA. However, in age groups 20−50 years, MRSA was two-fold higher in non-ICU (35%) than ICU (18.6%). Interestingly, a highly significant association was found between infection-site and age-groups (p-value 0.000). Skin infections remained higher in all ages; pediatrics 32.14%, adults 56%, and seniors 25% while respiratory infections were lower in pediatrics (14.3%) and adults (17%) while it was highest in seniors (38%). Blood and “other” sites in pediatrics were recorded (28.6%; 25%, respectively), and were slightly lower in adults (18.6%; 8.6%) and seniors (14%; 22.8%), respectively. Furthermore, a significant association existed between infection-site and MRSA (Chi-Square Test, p-value 0.002). Thus, the common cutaneous infections across all age-groups imply that skin is a significant reservoir for endogenous infections; particularly, for geriatrics MRSA. These findings have important clinical implications and in understanding S. aureus profiles and transmission dynamics across different age groups that is necessary for strategic planning in patient management and infection control.

Comparison of the Distribution and Changes in the Antibiotic Resistance of Clinical Bacterial Isolates from the Lower Respiratory Tract of Children in Shenzhen Before the Epidemic, During the Epidemic, and During the Period of Normalized Prevention and Control of COVID-19.

This study aimed to understand the impact of the coronavirus disease 2019 (COVID-19) epidemic on the distribution and antibiotic resistance of pathogenic bacteria isolated from the lower respiratory tract of children in our hospital. Antimicrobial susceptibility tests were performed on bacteria isolated clinically from the lower respiratory tracts of children in our hospital from 2018 to 2021 by the Kirby-Bauer method and automated systems. From 2018 to 2021, the top three lower respiratory tract clinical isolates in our hospital were Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae. These three species showed obvious seasonal epidemic patterns, and their numbers decreased significantly during the COVID-19 epidemic, from 4559 in 2019 to 1938 in 2020. Bacterial resistance to antibiotics also changed before and after the COVID-19 epidemic. The annual proportions of methicillin-resistant S. aureus (MRSA) were 41%, 37.4%, 26.2%, and 29.8%. The resistance rates of Klebsiella pneumoniae to ceftriaxone were 40.5%, 51.9%, 35.3%, and 53.3%, and the detection rates of carbapenem-resistant K. pneumoniae (CRKP) were 2.7%, 11.1%, 5.9%, and 4.4%. The detection rates of β-lactamase-producing H. influenzae were 51.9%, 59.2%, 48.9%, and 55.3%. The rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and β-lactamase-producing H. influenzae decreased significantly in 2020 compared with 2019, whereas that of carbapenem-resistant P. aeruginosa and carbapenem-resistant A. baumannii increased. The detection rates of β-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) gradually increased over the 4years. Protective measures against COVID-19, including reduced movement of people, hand hygiene, and surgical masks, may block the transmission of S. pneumoniae, H. influenzae, and M. catarrhalis and reduce the detection rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and β-lactamase-producing H. influenzae.

Klinik örneklerden izole edilen Staphylococcus aureus izolatlarının sıklığı ve antibiyotik duyarlılık sonuçlarının değerlendirilmesi: Üç Yıllık Veri

Objective: Staphylococci cause community-acquired and hospital-acquired infections, and Staphylococcus aureus is one of leading agents. In the last decades methicillin-resistant S.aureus (MRSA), vancomycin-intermediate S.aureus (VISA) and vancomycin-resistant S.aureus (VRSA) became as major concerns. Resistance to other antibiotics is also another growing issue. The aim of this study was to investigate the prevalence of S.aureus species and to evaluate susceptibilities to antimicrobial agents in a state (tertiary) hospital.&#x0D; Methods: Clinical cultures from various samples (urinary tract, respiratory, wound, abscess, tissue, catheter and external auditory) obtained from January 2017 to December 2019 in XXX hospital were included in the study. Isolated S.aureus strains and their antibiotic susceptibilities were retrospectively evaluated.&#x0D; Results: A total of 765 S.aureus strains were isolated. 165 S.aureus strains were found as methicillin resistant (MRSA; 21.9%). There was not any statistically significant difference in MRSA rates among evaluated years (p=0.772). There was not any strain that was resistant to vancomycin, teicoplanin and/or linezolid. The highest rate was observed in penicillin resistance (n=646/728, 88.7%). There was not any statistically significant alteration in the resistance rates of all tested antibiotics during the three-year period.&#x0D; Conclusions: Despite dwindling MRSA rates in UAMDSS, CAESAR report indicates that Turkey seems to be in the beginning phase of this struggle. Local and/or national antimicrobial stewardship programs are in effect in Turkey, but further measures are required.

Determination of Virulence Factors and Resistance Profile of Methicillin-Resistant Staphylococcus aureus Strains among Different Types of spa, agr, and SCCmec.

In order to restrict the spread of methicillin-resistant S. aureus (MRSA) in hospitals, it is necessary to characterize isolates rapidly and precisely. The objective of this study was to determine virulence factors and resistance profiles of MRSA strains among spa, agr, and SCCmec types. In total, 55 MRSA isolates were collected from clinical specimens. The MRSA isolates were characterized by antimicrobial susceptibility testing, virulence genes, agr typing, spa typing, and SCCmec typing. According to our findings, all MRSA strains were resistant to cefoxitin; 88% and 86.7% of which were resistant to erythromycin and clindamycin, respectively. Type II agr was predominant with 54.54% frequency. Among 27 different spa types, type t030 was most frequently (25.45%). Most MRSA isolates (63.3%) were SCCmec type III. The pvl and tst genes were found in 25.3% and 32.7% of MRSA isolates, respectively. Among the MRSA strains, ermA, ermB, and ermC were present in 50%, 33.3%, and 57.3% of cases, respectively. In addition, 43 of the 55 MRSA strains (78%) harbored aminoglycoside resistance genes. The results of our study revealed that the MRSA rate in our region is dramatically high. Better infection control guidelines in hospitals, as well as ongoing epidemiological surveillance studies, could be strongly suggested for effective prevention of the spread of MRSA to inpatients.

A fusidic acid-resistant (PVL+) clone is associated with the increase in methicillin-resistant Staphylococcus aureus in New Caledonia

ObjectivesSince 2014, Staphylococcus aureus methicillin resistance has been rapidly increasing in New Caledonia and is associated with potential serious clinical repercussions. In the present study, we investigated the epidemiology of methicillin-resistant S. aureus (MRSA) in New Caledonia and the possible emergence of a particular clonal strain. MethodsAn overview of the distribution of MRSA in New Caledonia in 2019 is presented. We collected and analysed 171 clinical MRSA isolates from New Caledonia medical laboratories during August and September 2019. Among this collection, 49 representative isolates were analyzed by the French National Reference Center for Staphylococci using the StaphyType DNA microarray, allowing genetic characterization of the isolates. ResultsAmong the 1144 S. aureus isolated over the year 2019, 442 isolates (39%) were resistant to methicillin, and 62% of these isolates were resistant to fusidic acid (FA). During the inclusion period, FA resistance rate was similar (60%). Genetic characterization evidenced CC6 as the predominant clonal complex (70%) with 26 isolates (53%) identified as CC6-MRSA-[IV+fus] (PVL+). ConclusionsThese findings demonstrated a low diversity of MRSA in New Caledonia, with the dominance of a clonal complex not reported previously. The frequent fusidic acid (FA) resistance in MRSA was associated with a high prevalence of fusC gene, suggesting that FA misuse contributed to driving the selection of this clone. Our findings suggest the recommendation to stop the topical use of FA to control the emergence of this severe MRSA clone and decrease the rate of MRSA in New Caledonia.

Rate of methicillin-resistant Staphylococcus aureus in pediatric emergency departments in Spain

IntroductionStaphylococcus aureus is a common germ in bacterial infections in children. The rate of methicillin-resistant S. aureus (MRSA) is increasing lately. ObjectivesThe main aim is to know the rate of positive cultures to MRSA in Spanish pediatric emergency departments. The secondary aims are to analyse the risk factors for MRSA isolation (patient origin, history of hospitalization or surgery in the previous 90 days, antibiotherapy in the previous 60 days, presence of comorbidity, invasive devices, prior MRSA isolation) and to analyse the morbidity of these infections. MethodologyRetrospective multicenter study (07/01/2017–06/30/2018) with review of patient histories with isolation of S. aureus in samples of any origin obtained in 8 pediatric emergency departments of the Infectious Diseases Working Group of the Spanish Society of pediatric Emergencies. ResultsDuring this period, S. aureus was detected in 403 patients (average age 75.8 ± 59.2 months; 54.8% male): 28.8% hospital-related infections (HRI) and 71.2% community-related infections (CRI). Overall, MRSA rate was 16.6% (95% CI: 13−20.2%); 18.1% in HRI and 16.2% in CRI (p > 0.05). The highest rates of MRSA were obtained in skin abscesses (29.3%, CI 95%: 21.8−36.8%), patients not born in Spain (52%; CI 95%: 32−72%) or patients with a previous MRSA infection (90%; CI 95% 71.4−100%).167 (41%) patients were admitted, 12 (3%) had complications and 4 (1%) suffered sequels. There were no deaths. ConclusionsThe overall MRSA rate was one in 6 staphylococcal infections. Higher MRSA rates were detected in samples of suppurating skin injuries and in foreign children or in children with a history of previous MRSA infection. In suppurative skin lesions, early drainage is essential and the change to an antibiotic with MRSA coverage should be considered if the evolution is inadequate.

Activity of Tedizolid and Comparator Agents Against Gram-positive Isolates Causing Skin and Skin Structure Infections in Pediatric Patients in United States Hospitals (2015-2019).

Tedizolid was approved by the United States Food and Drug Administration to treat acute bacterial skin and skin structure infections in adults in 2014, and in 2020, United States Food and Drug Administration expanded the approval of tedizolid to treat pediatric patients 12 years of age and older. This study assessed the activity of tedizolid and comparator agents against clinical surveillance isolates collected from pediatric patients with skin and skin structure infection in the United States. A total of 2747 gram-positive organisms (1 per patient) were collected in 2015 to 2019 from pediatric (≤17 years old) patients with skin and skin structure infections. The isolates were collected from 33 US medical centers and susceptibility tested against tedizolid and comparators by reference broth microdilution methods. Susceptibility results for main pathogens were stratified by patient age: ≤1 years old (851 isolates), 2 to 5 years old (623), 6 to 12 years old (754) and 13 to 17 years old (519). Staphylococcus aureus (n = 2163) was the main pathogen recovered from all age groups, followed by β-hemolytic streptococci (n = 460). Tedizolid inhibited all S. aureus , including methicillin-resistant S. aureus (MRSA) isolates (41.0%), regardless of the age group. MRSA rates varied by age group; MRSA was highest among ≤1 years old (45.0%) and lowest in the 13 to 17 years old (32.7%) groups. Linezolid, daptomycin and vancomycin also displayed susceptibility rates of 100% against S. aureus isolates. Clindamycin (81.3%-98.5%), tetracycline (91.6%-97.1%) and trimethoprim-sulfamethoxazole (97.0%-100%) susceptibility rates varied among age groups and methicillin resistance profiles. Overall, tedizolid, linezolid, daptomycin and vancomycin inhibited all gram-positive pathogens in this collection. Tedizolid was very active against a large collection of gram-positive pathogens causing skin and skin structure infection in pediatric patients, including MRSA isolates.

The Molecular Characterization of Virulence Determinants and Antibiotic Resistance Patterns in Human Bacterial Uropathogens.

The high rates of bacterial infections affect the economy worldwide by contributing to the increase in morbidity and treatment costs. The present cross-sectional study was carried out to evaluate the prevalence of bacterial infection in urinary tract infection (UTI) patients and to evaluate the antimicrobial resistance rate (AMR) in a Tertiary Care Hospital in Lahore, Pakistan. The study was conducted for the period of one year from January 2020 to December 2020. A total of 1899 different clinical samples were collected and examined for bacterial cultures using standard procedures. Samples were inoculated on different culture media to isolate bacterial isolates and for identification and susceptibility testing. A total of 1107/1899 clinical samples were positive for Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and other bacterial isolates. Methicillin-resistant S. aureus (MRSA) prevalence was 16.93% from these positive cases. MRSA strains were found to be highly resistant to amikacin, clindamycin, fusidic acid, gentamicin and tobramycin, while highest sensitivity was noted against vancomycin (100%) and linezolid (100%). MRSA and high rates of multidrug resistance (MDR) pose a serious therapeutic burden to critically ill patients. A systematic and concerted effort is essential to rapidly identify high-risk patients and to reduce the burden of AMR.

Mathematical modelling of the combined effect of propolis extract and Origanum compactum essential oil on the growth of methicillin resistant Staphylococcus aureus

Staphylococcus aureus is a commensal human pathogen responsible of several infectious diseases, especially nosocomial infections. Its rapid spread and ability to resist to environmental conditions make it a serious threat for public health. The aim of this study was to investigate the combined antibacterial effect of propolis extract and Origanum compactum essential (OCEO) against methicillin resistant S. aureus (MRSA), and to build a mathematical model predicting this effect. Propolis and OCEO were collected from the north of Morocco. The minimal inhibitory concentration (MIC) of each product was determined by the microdilution method. The kinetics of MRSA growth was evaluated in absence and in presence of ethanol extract of propolis (EEP) and OCEO, each alone and in combination. The mathematical modelling was made by a polynomial regression. EEP and OCEO showed strong antibacterial activity against MRSA. The MIC of EEP was 0.625 mg/mL and the MIC of OCEO was 1%. The two products showed significant reduction in the growth rate of MRSA, and that as a function of concentration. The combination of EEP and OCEO showed strong synergistic interaction, noticed by growth rate reduction. A mathematical model describing the growth of MRSA in presence of EEP and OCEO was generated. By the negative signs of the coefficients of EEP and OCEO in the linear part, the model confirmed they synergistic interaction. From the obtained results it can be concluded that the combination of propolis extract and O. compactum EO is an interesting approach to control MRSA infections.

Multidrug-resistant and enterotoxigenic methicillin-resistant Staphylococcus aureus isolated from raw milk of cows at small-scale production units.

Objective:Staphylococcus aureus (S. aureus) has evolved as one of the most significant bacteria causing food poisoning outbreaks worldwide. This study was carried out to investigate the prevalence, antibiotic sensitivity, virulence, and enterotoxin production of S. aureus in raw milk of cow from small-scale production units and house-raised animals in Damietta governorate, Egypt.Material and Methods:The samples were examined bacteriologically, and antimicrobial sensitivity testing was carried out. Moreover, isolates were characterized by the molecular detection of antimicrobial resistance, virulence, and enterotoxin genes.Results:Out of 300 milk samples examined, S. aureus was isolated from 50 samples (16.7%). Antibiotic sensitivity testing revealed that isolates were resistant to β-lactams (32%), tetracycline (16%), and norfloxacin (16%); however, they showed considerable sensitivity to ceftaroline and amikacin (72%). Multidrug-resistance (MDR) has been observed in eight isolates (16%), with a MDR index (0.5) in all of them. Of the total S. aureus isolates obtained, methicillin-resistant S. aureus (MRSA) has been confirmed molecularly in 16/50 (32%) and was found to carry mecA and coa genes, while virulence genes; hlg (11/16, 68.75%) and tsst (6/16, 37.5%) were amplified at a lower percentage, and they showed a significant moderate negative correlation (r = −0.59, p-value > 0.05). Antibiotic resistance genes have been detected in resistant isolates relevant to their phenotypic resistance: blaZ (100%), tetK (50%), and norA (50%). Fifty percent of MRSA isolates carried the seb enterotoxin gene.Conclusion:High detection rate of MRSA and MDR isolates from milk necessitates the prompt implementation of efficient antimicrobial stewardship guidelines, especially at neglected small-scale production units.

176. Antibiotic Resistance Patterns, Seasonality, and Correlation with the Influenza Season in the United States: A Multicenter Evaluation Reveals Surprising Association Between Influenza Season and Gram Negative Pathogens

BackgroundInfluenza infection may affect bacterial transmission dynamics and seasonality of antimicrobial resistance (AMR). There is a paucity of data on the association of influenza season and AMR rates. We aimed to describe trends of AMR and their correlation with the influenza season in ambulatory and inpatient settings in the United States (US). MethodsWe used the BD Insights Research Database (Franklin Lakes, NJ USA) to identify 30 day non-duplicate isolates collected from patients >17 years old with susceptibility profile of Gram-negative (GN) (Enterobacterales (ENT), P. aeruginosa (PSA), A. baumannii spp. (ACB), and S. maltophilia (Sm)) and Gram-positive (GP) pathogens (S. aureus (SA), and S. pneumoniae (Sp)) in up to 257 US healthcare institutions from 2011-19. We defined the outcomes as rates per 100 admissions and % of non-susceptibility (NS), stratified by community and inpatient settings, resistance type (resistance to carbapenem (Carb-NS), quinolone (FQ-NS), macrolide (Macr NS), penicillin (PCN NS), and extended spectrum cephalosporin (ESC NS)) and isolate origin (respiratory and non-respiratory). Influenza data were presented as the % of positive laboratory tests. We used descriptive statistics and generalized estimating equations models to evaluate the monthly trends of AMR outcomes and correlation with the influenza season.ResultsWe identified 16 576 274 confirmed non-duplicate pathogens, of which 154 841 were GN Carb-NS, 1 502 796 GN FQ-NS, 498 012 methicillin resistant SA (MRSA), and 44 131 Macr-NS, PCN-NS, and ESC-NS Sp. Among the Carb-NS pathogens, Influenza rate was correlated with % ACB-NS [β= 0.205, p< .001]. In the FQ-NS group, influenza was associated with overall % ENT-NS [β= 0.041 p< .001] and % PSA-NS [β= 0.039, p = .015]. For the GP pathogens, all Sp. rates were correlated with increased influenza positivity % (See Table). Only MRSA rates of respiratory source were associated with influenza [β= .066, p=.028].Summary of Multivariate regressions of AMR and % Flu by Source and Setting (controlling for hospital level factors): 2011-2019 Data in each cell is presented as the coefficient and p-value is in parentheses. ^adjusted for region, teaching, urban, bed size, and season. + p<.10 *p <.05 **p <.01 ***p <.001ConclusionOur study revealed surprising association between influenza epidemics and GN resistance and corroborated the evidence of correlation between respiratory GP and influenza infections. These insights may help inform targeted antimicrobial stewardship initiatives during influenza season.Disclosures Amine Amiche, PhD, Sanofi (Employee, Shareholder) Heidi Kabler, MD, Sanofi Pasteur (Employee) Janet Weeks, PhD, Becton, Dickinson and Company (Employee) Kalvin Yu, MD, BD (Employee) Vikas Gupta, PharmD, BCPS, Becton, Dickinson and Company (Employee, Shareholder)

Molecular Confirmation of Vancomycin-Resistant Staphylococcus aureus with vanA Gene from a Hospital in Kathmandu.

Staphylococcus aureus, a commensal on the skin and in the nasal cavity of humans, is one of the most serious cases of nosocomial infections. Moreover, methicillin-resistant S. aureus (MRSA) is a leading cause of morbidity and mortality worldwide. For the treatment of MRSA infections, vancomycin is considered as a drug of choice. However, the emergence of vancomycin resistance among MRSA isolates has been perceived as a formidable threat in therapeutic management. To estimate the rate of vancomycin-resistant S. aureus (VRSA) and to detect the vancomycin-resistant genes, namely, vanA and vanB, among the isolates, a hospital-based cross-sectional study was conducted from July to December 2018 in Annapurna Neurological Institute and Allied Science, Kathmandu, Nepal. S. aureus was isolated and identified from different clinical samples and processed for antibiotic susceptibility testing by the modified Kirby–Bauer disc diffusion method. The screening of MRSA was performed as per Clinical and Laboratory Standard Institute (CLSI) guidelines. VRSA was confirmed by the minimum inhibitory concentration (MIC) method by employing E-test strips. All the phenotypically confirmed VRSA were further processed to detect the vanA and vanB gene by using the conventional polymerase chain reaction (PCR) method. A total of 74 (20.3%) S. aureus were isolated, and the highest percentage of S. aureus was from the wound samples (36.5%). Of 74 S. aureus isolates, the highest number (89.2%) was resistant to penicillin, and on the other hand, linezolid was found to be an effective drug. Likewise, 45 (60.81%) were found to be MRSA, five (11.11%) were VRSA, and 93.2% of S. aureus isolates showed an MAR index greater than 0.2. Two VRSA isolates (40%) were positive for the vanA gene. The higher prevalence of MRSA and significant rate of VRSA in this study recommend routine surveillance for the MRSA and VRSA in hospital settings before empirical therapy.

Tasa de Staphylococcus aureus resistentes a meticilina en urgencias pediátricas en España

IntroductionStaphylococcusaureus (S. aureus) is a common germ present in bacterial infections in children. Lately, the rate of methicillin-resistant S. aureus (MRSA) is increasing. ObjectivesThe main aim of this study is to know the rate of positive cultures to MRSA in Spanish pediatric emergency departments. The secondary aims are to analyze the risk factors for MRSA isolation (patient origin, history of hospitalization or surgery in the previous 90 days, antibiotherapy in the previous 60 days, presence of comorbidity, invasive devices, prior MRSA isolation) and to analyze the morbidity of these infections. MethodologyRetrospective multicenter study (07/01/2017–06/30/2018) with review of patient histories with isolation of S. aureus in samples of any origin obtained in 8 pediatric emergency departments of the Infectious Diseases Working Group of the Spanish Society of Pediatric Emergencies. ResultsDuring this period, S. aureus was detected in 403 patients (average age 75.8±59.2 months; 54.8% male): 28.8% hospital-related infections and 71.2% community-related infections. Overall, MRSA rate was 16.6% (95% CI: 13-20.2%); 18.1% in hospital-related infections and 16.2% in community-related infections (P>.05). The highest rates of MRSA were obtained in skin abscesses (29.3%, 95% CI: 21.8-36.8%), patients not born in Spain (52%; 95% CI: 32-72%) or patients with a previous MRSA infection (90%; 95% CI: 71.4-100%).167 (41%) patients were admitted, 12 (3%) had complications and 4 (1%) suffered sequels. There were no deaths. ConclusionsThe overall MRSA rate was one in six staphylococcal infections. Higher MRSA rates were detected in samples of suppurating skin injuries and in foreign children or in children with a history of previous MRSA infection. In suppurative skin lesions, early drainage is essential and the change to an antibiotic with MRSA coverage should be considered if the evolution is inadequate.