Proportion Of Methicillin-resistant Staphylococcus Aureus Research Articles

Wound colonization with methicillin-resistant Staphylococcus aureus and hypotheses about acquisition routes in rural health care settings in Sub-Saharan Africa: Perspective from a center devoted to the treatment of cutaneous neglected tropical diseases

We identified a high prevalence (46.4%) of wound colonization with methicillin-resistant Staphylococcus aureus (MRSA) in patients hospitalized in a center devoted to the treatment of cutaneous tropical diseases in Benin. The proportion of MRSA among Saureus isolates was 54.3%. Thirty percent of these MRSA were identified in outpatients. The analysis of pulsed-field gel electrophoresis demonstrated an important diversity of strains but also identified 8 small clusters containing between 2 and 4 isolates suggesting cross-transmission.

Prevalence of Methicillin-Resistant Staphylococcus aureus in Nasal Cavity of Medical Students at Shendi University, Sudan

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is becoming ever more prevalent in Sudan, and the proportion of MRSA to methicillin-sensitive Staphylococcus aureus (MSSA) seems to be increasing. New strains of MRSA are ever-developing resistance to antibiotic treatment, increasing morbidity and mortality rate.
 Objectives: To detect the prevalence of methicillin-resistant Staphylococcus aureus in the nasal cavity of medical students at Shendi University and to detect variations of MRSA Colonization between student smokers and non-smoker students.
 Methodology: 60 swabs were collected from medical students of Shendi University, culture, and direct gram stain were done, then the plates were examined for any significant bacterial growth. The isolated bacteria were then identified by colonial morphology, indirect gram stain, and biochemical tests.
 Results: All data were analyzed using Statistical Package for Social Sciences (SPSS). Of these, 66.7 % (40/60) were males. 33.3% (20/60) were females. The isolated organism was Staphylococcus aureus 24 (40%), with no growth 36 (60%). The study showed that the overall resistance of Staphylococcus aureus to Methicillin was 21 (35%) and 3 (5%) Sensitive to Methicillin. Methicillin-resistant Staphylococcus aureus cases were found in nine (100%) of the students who smoked and twelve (80%) of the students who did not smoke. Of the pupils who did not smoke, three (20%) had Staphylococcus aureus. Methicillin Sensitive.
 Conclusion: The carriage rate of S. aureus is consistent with similar studies. MRSA carriage in this university study appears high as compared to the general population. Although this study did not confirm a variety of risk factors for the carriage of MRSA previously identified by others, university healthcare personnel should be aware of the changing epidemiology of MRSA and the preventive measures needed to avoid outbreaks.

Rapid identification of MRSA directly from sterile body fluids by co-magnetic bead enrichment and MALDI-TOF mass spectrometry

As a result of the extensive use of antibiotics, methicillin-resistant Staphylococcus aureus (MRSA) has emerged, leading to serious clinical and epidemiological problems. This study established a rapid and accurate method for detection of MRSA in clinical samples. The MRSA detection procedure involved a magnetic separation technique and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the characteristic peaks of proteins were compared to achieve the detection of MRSA. We treated PBS, blood and cerebrospinal fluid with MRSA, and identified it after short-term culture. The time and detection limit for identifying MRSA were determined. At the same time, we used the method to detect different proportions of mixed bacteria. The results revealed that the enrichment efficiency of Amp-MBs for MRSA in PBS, blood and cerebrospinal fluid was greater than 95 %, 80.95 % and 83.6 %, respectively. The whole detection process could be completed within 1.5 h. The negative and positive percent agreement of MRSA detection were 83 % and 95 %, respectively. In mixed bacterial samples, bacteria can be detected when the proportion of MRSA is greater than 50 %. Overall, this study provides an effective method for bacterial preconcentration and detection, which has high potential for rapid and sensitive diagnosis of MRSA infection

Methicillin-Resistant Staphylococcus aureus Bloodstream Infections in Hospitalized Patients in Peru.

There is a knowledge gap in the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) causing bloodstream infections (BSIs) in Peru. Through a surveillance study in 13 hospitals of 10 Peruvian regions (2017-2019), we assessed the proportion of MRSA among S. aureus BSIs as well as the molecular typing of the isolates. A total of 166 S. aureus isolates were collected, and 36.1% of them were MRSA. Of note, MRSA isolates with phenotypic and genetic characteristics of the hospital-associated Chilean-Cordobes clone (multidrug-resistant SCCmec I, non-Panton-Valentine leukocidin [PVL] producers) were most commonly found (70%), five isolates with genetic characteristics of community-associated MRSA (CA-MRSA)-SCCmec IV, PVL-producer-(8.3%) were seen in three separate regions. These results demonstrate that hospital-associated MRSA is the most frequent MRSA found in patients with BSIs in Peru. They also show the emergence of S. aureus with genetic characteristics of CA-MRSA. Further studies are needed to evaluate the extension of CA-MRSA dissemination in Peru.

Molecular characterization of MRSA collected during national surveillance between 2008 and 2019 in the Netherlands

Background.Although the Netherlands is a country with a low endemic level, methicillin-resistant Staphylococcus aureus (MRSA) poses a significant health care problem. Therefore, high coverage national MRSA surveillance has been in place since 1989. To monitor possible changes in the type-distribution and emergence of resistance and virulence, MRSA isolates are molecularly characterized.Methods.All 43,321 isolates from 36,520 persons, collected 2008–2019, were typed by multiple-locus variable number tandem repeats analysis (MLVA) with simultaneous PCR detection of the mecA, mecC and lukF-PV genes, indicative for PVL. Next-generation sequencing data of 4991 isolates from 4798 persons were used for whole genome multi-locus sequence typing (wgMLST) and identification of resistance and virulence genes.Results.We show temporal change in the molecular characteristics of the MRSA population with the proportion of PVL-positive isolates increasing from 15% in 2008–2010 to 25% in 2017–2019. In livestock-associated MRSA obtained from humans, PVL-positivity increases to 6% in 2017–2019 with isolates predominantly from regions with few pig farms. wgMLST reveals the presence of 35 genogroups with distinct resistance, virulence gene profiles and specimen origin. Typing shows prolonged persistent MRSA carriage with a mean carriage period of 407 days. There is a clear spatial and a weak temporal relationship between isolates that clustered in wgMLST, indicative for regional spread of MRSA strains.Conclusions.Using molecular characterization, this exceptionally large study shows genomic changes in the MRSA population at the national level. It reveals waxing and waning of types and genogroups and an increasing proportion of PVL-positive MRSA.

Methicillin resistant Staphylococcus aureus isolated from surgical patients in Cambodia over a 10-year period.

Methicillin-resistant Staphylococcus aureus (MRSA) related surgical infections are a global challenge. The burden of antimicrobial resistance is high throughout South-East Asia, and this is reflected in our local institution in Cambodia. Between 2011 and 2013, we analysed 251 wound swab samples at the Children's Surgical Centre, Phnom Penh; 52.5% of the Staphylococcus aureus isolates (n = 52/99) were MRSA positive. Ten years on, we have sought to investigate whether there is a difference in MRSA rates within our adult and paediatric patient population. Between 2020 and 2022, MRSA rates in our patient population have remained similar at 53.8% (n = 42/78). Resistance profiles of MRSA isolates have also remained similar with a significant proportion of MRSA still showing sensitivity to trimethoprim-sulfamethoxazole and tetracycline. We also find that patients presenting with wound infection secondary to trauma or orthopaedic implants had greater propensity to yield MRSA.

Isolation of pathogenic strains of methicillin-resistant Staphylococcus aureus from mobile phones in a tertiary institution in Ibadan, Nigeria

The health implications of mobile phones emission have been a matter of concern to health practitioners for decades but little or no attention has been given to the mobile phones as potential fomites for pathogens. This study isolated and characterised methicillin-resistant Staphylococcus aureus (MRSA) on mobile phones of students in a tertiary institution in Ibadan, Nigeria. One hundred swab samples were obtained from the surfaces of mobile phones of students in a cross-sectional study conducted between July and August, 2019. Presumptive staphylococci were isolated on mannitol salt agar and identities were confirmed by standard biochemical test and Gram-staining. Antimicrobial susceptibility test was done by disc-diffusion method and mecA or mecALGA251, tsst-1, eta and etb genes screened by PCR technique. Among the 200 presumptive S. aureus isolated, 163 (81.5%) were confirmed as S. aureus exhibiting resistance to ofloxacin (1.8%), gentamicin (3.7%), ceftriaxone (29.4%), ceftazidime (57.7%), cefoxitin (61.3%), cefuroxime (64.4%), erythromycin (85.3%), amoxicillin-clavulanic acid (86.5%) and cloxacillin (92%). Proportion of MRSA and methicillin-susceptible S. aureus (MSSA) were 61.3% and 38.7% respectively with significant difference in their level of antibiotic resistance to the cephalosporins (excluding ceftriaxone), penicillins, erythromycin and ofloxacin (p<0.05). All the MRSA strains were multidrug resistant (MDR) harbouring mecA or mecALGA251 (56.3%), tsst-1 (56.3%), etb (31.3%) and eta (12.5%) genes. This study detected a high proportion of methicillin-resistant, virulent S. aureus as fomites on surfaces of mobile phones among students of a tertiary institution. This is of public health concern and thus requires strong public education to avoid imminent spread and outbreaks.

Prevalence and Antimicrobial Resistance Profile of Methicillin Resistant Staphylococcus aureus isolates from Wound Infections in Zaria, Nigeria.

Methicillin Resistant Staphylococcus aureus (MRSA) has been a major culprit in many problematic infections especially in wound infections due to its failure to respond to antibiotics and a leading bacterial agent in community acquired infections and infections acquired in hospitals. This study investigated the prevalence and antibiotic resistant profile of MRSA in patients with wound infections in Zaria. Two hundred and seventy-two wound swabs were collected from three hospitals in Zaria, Kaduna State. These were analyzed using standard microbiological and biochemical procedures for staphylococcal isolation. Confirmed S. aureus isolates were evaluated for methicillin resistance using cefoxitin disc and multidrug resistance status. Of the 272 suspected Staphylococcal isolates analyzed, 73 (27%) were confirmed as S. aureus isolates, of which 63 (86 %) were MRSA. The infection rate of MRSA was found to be higher in males than in females. MRSA strains were 100 % resistant to the β- lactam antibiotics, with 57.1 % being multidrug resistant, but were susceptible to Gentamicin, Ciprofloxacin, Trimethoprim-sulphamethoxazole and Tetracycline. We recorded a high proportion of MRSA and Multidrug resistant-MRSA isolates from wound infections in Zaria, thus, much emphasis on infection control measures should be prioritized. There is the need to increase the effectiveness of prevention and infection control measures as well as treatment of MRSA infections.

Cfr and fexA genes in methicillin-resistant Staphylococcus aureus from humans and livestock in the Netherlands

BackgroundAlthough the Netherlands is a country with a low endemic level of methicillin-resistant Staphylococcus aureus (MRSA), a national MRSA surveillance has been in place since 1989. In 2003 livestock emerged as a major reservoir of MRSA and currently livestock-associated MRSA (clonal complex CC398) make up 25% of all surveillance isolates. To assess possible transfer of resistant strains or resistance genes, MRSA obtained from humans and animals were characterized in detail.MethodsThe sequenced genomes of 6327 MRSA surveillance isolates from humans and from 332 CC398 isolates from livestock-related samples were analyzed and resistance genes were identified. Several isolates were subjected to long-read sequencing to reconstruct chromosomes and plasmids.ResultsHere we show the presence of the multi-resistance gene cfr in seven CC398 isolates obtained from humans and in one CC398 isolate from a pig-farm dust sample. Cfr induces resistance against five antibiotic classes, which is true for all but two isolates. The isolates are genetically unrelated, and in seven of the isolates cfr are located on distinct plasmids. The fexA gene is found in 3.9% surveillance isolates and in 7.5% of the samples from livestock. There is considerable sequence variation of fexA and geographic origin of the fexA alleles.ConclusionsThe rare cfr and fexA resistance genes are found in MRSA from humans and animals in the Netherlands, but there is no evidence for spread of resistant strains or resistance plasmids. The proportion of cfr-positive MRSA is low, but its presence is worrying and should be closely monitored.

Epidemiology and microbiology of fracture-related infection: a multicenter study in Northeast China

ObjectiveThis study aimed to explore the epidemiological and microbiological characteristics of fracture-related infection (FRI), analyze the drug resistance characteristics of major pathogens, and provide timely and relatively complete clinical and microbiological data for antimicrobial treatment of FRI.MethodsThe clinical and microbiological data of patients with FRI from January 1, 2011, to December 31, 2020, were collected from three tertiary hospitals in Northeast China. The automatic microbial analysis system was used for strain identification and drug susceptibility testing, and the drug susceptibility results were determined in accordance with the latest Clinical and Laboratory Standards Institute (CLSI) criteria (as applicable each year).ResultsA total of 744 patients with FRI were enrolled. The incidence of FRI was about 1.5%, and 81.7% were male patients, with an average age of 48.98 ± 16.01 years. Open fractures accounted for 64.8%. Motor crush (32.8%) and falling (29.8%) were the main causes of injuries. The common sites of infection were the tibia and fibula (47.6%), femur (11.8%), foot (11.8%), and hand (11.6%). A total of 566 pathogenic bacteria were cultured in 378 patients with positive bacterial cultures, of which 53.0% were Gram-positive bacteria and 47.0% were Gram-negative bacteria. The most common pathogen at all sites of infection is Staphylococcus aureus. Staphylococcus aureus had a high resistance rate to penicillin (PEN), erythromycin (ERY), and clindamycin (CLI), exceeding 50%. Methicillin-resistant Staphylococcus aureus (MRSA) was more than 80% resistant to CLI and ERY.ConclusionsThe incidence of FRI in Northeast China was at a low level among major medical centers nationwide. Staphylococcus aureus was still the main pathogen causing bone infections, and the proportion of MRSA was lower than reported abroad, but we have observed an increase in the proportion of infections. Enterobacteriaceae have a higher resistance rate to third-generation cephalosporins and quinolones. For Enterobacteriaceae, other sensitive treatment drugs should be selected clinically.

What Is Driving the Epidemiology of Methicillin-Resistant Staphylococcus aureus Infections in Europe?

Introduction: The burden from infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in the European Union/European Economic Area (EU/EEA) has increased in recent years, especially in the higher prevalence southern and eastern countries. Addressing this challenge requires a clear knowledge of the factors driving this epidemiology to inform effective national interventions and campaigns. Methods: We identified national quality metrics for antibiotic use and hand hygiene from the 2016/2017 European Centre for Disease Control (ECDC) Point Prevalence study as well as structural, cultural, and governance indicators from other sources. We then utilized general linear modeling to identify parsimonious correlations with national MRSA proportions reported by the European Antimicrobial Resistance Surveillance Network (EARS-Net). Results: The main process predictor of MRSA prevalence in EU/EEA countries was the use of more than one concurrent antibiotic per patient. The impact of hand hygiene was less clear, possibly because consumption of alcohol hand-rub was suboptimal throughout Europe. Hospital and infection control structural factors did not appear relevant at overall national level. Culture and governance were collectively key predictor groups; uncertainty avoidance, masculinity, and corruption indices strongly correlated with MRSA prevalence. Discussion: Our results suggest that the critical antibiotic stewardship factor associated with MRSA in EU/EEA countries is the quality of antibiotic prescribing, especially spectrum of activity, rather than overall consumption levels in hospitals or proportion of patients treated. Above all, MRSA hyperendemicity is correlated with a set of sociocultural behavioral constructs that typically manifest themselves in lack of urgency to address risk and normalization of deviance in relation to noncompliant practices.

Vancomycin MIC and agr dysfunction in invasive MRSA infections in southern Brazil.

In methicillin-resistant Staphylococcus aureus (MRSA) treatment, the vancomycin minimum inhibitory concentration (MIC) increase, vancomycin heteroresistance (hVISA) presence, and accessory gene regulator (agr) dysfunction are predictors of vancomycin therapy failure. This study evaluated the association between vancomycin MIC (≥ 1.0μg/mL) and agr dysfunction in invasive MRSA isolates. Vancomycin MIC, hVISA phenotype, agr group, and function were determined in 171 MRSA isolates obtained between 2014 and 2019 from hospitals in Porto Alegre, Brazil. All MRSA were susceptible to vancomycin; 16.4% of these had MIC ≥ 1.0μg/mL. Seventeen MRSA isolates expressed the hVISA phenotype; 35.3% of them had MIC of 1.5μg/mL. agr groups I (40.9%) and II (47.1%) were the most found groups for MRSA and hVISA isolates, respectively. The proportion of MRSA with vancomycin MIC ≥ 1.0μg/mL in agr group II was significantly higher than in agr groups I and III (p = 0.002). agr dysfunction was observed in 4.7% (8/171) of MRSA, especially those with vancomycin MIC ≥ 1.0μg/mL (p < 0.001). In addition, six isolates (35.3%; 6/17) with hVISA phenotype presented agr dysfunction, which was significantly higher than that in non-hVISA phenotype (p < 0.001). In conclusion, agr dysfunction in MRSA is associated with vancomycin MIC ≥ 1.0μg/mL and hVISA phenotype, which suggests that agr dysfunction might confer potential advantages on MRSA to survive in invasive infections.

Risk Factors Associated With Hospital-Onset MRSA Proportion—National Healthcare Safety Network, 2017–2018

Background:Staphylococcus aureus is frequently implicated in healthcare-associated infections in the United States, and a substantial proportion of these infections are attributed to methicillin-resistant Staphylococcus aureus (MRSA). Although MRSA infections have decreased in health care settings, accurate estimates of the rate of decline call for risk-adjusted methods for calculating the resistant proportion (%R), that is, the proportion of S. aureus resistant to cefoxitin or oxacillin. Risk-adjusted %R also enables more accurate interhospital comparisons and can serve as a quantitative guide and evaluation metric for prevention efforts. Methods: To develop a risk-adjusted %R for S. aureus, we analyzed the antimicrobial susceptibility test (AST) results for S. aureus isolates reported to the CDC NHSN Antimicrobial Resistance Option during 2017–2018. Isolates were reported for cerebrospinal fluid (CSF), blood, lower respiratory tract (LRT), and urine. Isolates without cefoxitin and oxacillin test results, or from the facilities that had &gt;10% missing test results were excluded. Test results were differentiated between those associated with community-onset and hospital-onset (HO) infections by defining the latter group as test results for isolates obtained 3 days or more after hospital admission. Logistic regression was used to evaluate the factors associated with oxacillin/cefoxitin resistance. Hospital, patient and isolate-level variables from NHSN annual survey and AR option were assessed as covariates. Variable entry into the models is based on significance level P &lt; .05. Results: Among 9,992 hospital-onset SA isolates from 9,019 patients in 315 facilities, 5,488 (54.9%) were MRSA. Logistic regression showed that a higher proportion of HO-MRSA was significantly associated with older age, female, particular sources of specimen (urine and LRT), and selected hospital characteristics: hospitals not serving as major teaching hospitals, hospitals with a higher proportion of MRSA among community-onset SA isolates, hospitals with lower percentage of beds in intensive care units, and hospitals outsourcing AST service (Table 1). Conclusions: HO-MRSA is independently associated with community burden of MRSA, older and female patient populations, and hospital teaching status and AST practices, which highlights the importance of public health engagement and regional collaborations to prevent MRSA. To provide a standardized MRSA proportion for public health surveillance, taking some of these factors into account in MRSA proportion standardization should be considered.Funding: NoneDisclosures: None

Dynamic Changes of Staphylococcus aureus Susceptibility to Vancomycin, Teicoplanin, and Linezolid in a Central Teaching Hospital in Shanghai, China, 2008-2018.

Vancomycin, teicoplanin, and linezolid are the major treatment options for methicillin-resistant Staphylococcus aureus (MRSA). The phenomenon of progressive increase in the value of vancomycin minimum inhibitory concentration (MIC) for S. aureus (i.e., vancomycin MIC “creep”), has been reported; however, it is still a controversial concept because the results of research remain inconclusive. In this study, we conducted a retrospective epidemiologic investigation for more than 10 years to elucidate the dynamic changes of the MICs of vancomycin, teicoplanin, and linezolid in S. aureus in a central teaching hospital in Shanghai, China. A total of 2911 S. aureus isolates was recovered from 2008 to 2018, to which the MICs of three antimicrobials were tested by the E-test method and subsequently correlated with the characteristics of oxacillin susceptibility, clonotypes, and antimicrobial consumption during the study period. The proportion of MRSA dramatically decreased from 2008 to 2018 (from 84 to 49%, p < 0.001). Vancomycin MIC decline was identified both in MRSA and methicillin-sensitive S. aureus (MSSA) (both with p < 0.001), and both the dominating MRSA clone ST5 and pre-dominating MRSA clone ST239 displayed vancomycin MIC decline (p < 0.001, p = 0.040), while teicoplanin MIC decline was only identified in MRSA (p = 0.037). Linezolid MIC creep was identified in total S. aureus (p < 0.001), but linezolid in MRSA as well as teicoplanin and linezolid in MSSA displayed no statistically distinct trends of MIC creep or decline. Clinical consumption of linezolid increased significantly from 2012 to 2018 (p = 0.003), which correlated with vancomycin MIC decline in S. aureus (p = 0.005). The results of this study clearly demonstrate the dynamic changes of the MICs of these three primary antimicrobials in S. aureus, and suggest that changes in clinical antibiotic use may affect bacterial resistance.

Methicillin-Resistant Staphylococcus Aureus (MRSA) in Poultry Species in Algeria: Long-Term Study on Prevalence and Antimicrobial Resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) is a well-known pathogen with a serious impact on human and veterinary public health. To determine antibiotic resistance of MRSA in poultry, 4248 nasal swabs were collected from 840 poultry farms in 18 different Wilayas (provinces) of Algeria. Swabs were collected between 2011 and 2018 from breeding hens, laying hens, broilers, and turkeys. Identification was carried out by the classical culture methods, and the disc diffusion test was used to determine the antibiotic resistance patterns. S. aureus was isolated from 477 (56.8%) farms, and flock prevalence was 52.8%, 48.8%, 48.4%, and 75.6% in breeding hens, laying hens, broilers, and turkeys, respectively. MRSA was isolated from 252 (30%) farms and flock prevalence was 22%, 33.5%, 27.4%, and 36%, respectively. As expected, all MRSA isolates were resistant to cefoxitin, penicillin G, amoxicillin/clavulanic acid, and oxacillin. High levels of resistance were found for tetracycline (82.5%), erythromycin (70.6%), clindamycin (68.6%), and ciprofloxacin (50%). Almost all isolates were susceptible to vancomycin (100%) and mupirocin and rifampicin (99.2%), followed by chloramphenicol (82.3%), and gentamicin (76%). This moderate proportion of MRSA in poultry poses a considerable risk to public health. The results of this study highlight the need for control programs that encompass primary animal production and the food chain to mitigate contamination and spread of MRSA in the poultry industry of Algeria, and consequently to humans.

Characteristics of Staphylococcus aureus Isolated From Clinical Specimens in a Tertiary Care Hospital, Kathmandu, Nepal.

Introduction:Methicillin resistant Staphylococcus aureus (MRSA) is a major human pathogen associated with nosocomial and community infections. mecA gene is considered one of the important virulence factors of S. aureus responsible for acquiring resistance against methicillin. The main objective of this study was to explore the prevalence, antibiotic susceptibility pattern, and mec A gene.Methods:A total of 39 isolates of S. aureus were isolated from 954 clinical specimens processed in Microbiology laboratory of Himal Hospital, Kathmandu. Antimicrobial susceptibility test (AST) was performed by Kirby-Bauer disc diffusion method using cefoxitin, and performed Polymerase Chain Reaction (PCR) for amplification of mecA gene in MRSA isolates.Results:Out of 954 clinical samples, (16.2%; 153/954) samples had bacterial growth. Among 153 culture positive isolates, 25.5% (39/153) were positive for S. aureus. Among 39 S. aureus (61.5%; 24/39) were multiple drug resistant (MDR). On AST, amoxicillin was detected as the least effective while vancomycin was the most effective. The prevalence of methicillin resistance was 46% (18/39) of which 72.2% (13/18) were positive for mecA gene in PCR assay.Conclusion:One in 4 culture positive isolates from the clinical specimens were S. aureus, of which almost two-thirds were MDR. Around half of the MDR showed MRSA and significant proportion of them were positive for mecA gene. This study concludes that the mecA gene is solely dependent for methicillin resistance in S. aureus but the presence of gene is not obligatory. PCR detection of the mecA gene is reliable, valid and can be suggested for the routine use in diagnostic laboratories.

Methicillin-Resistant Staphylococcus aureus (MRSA): Prevalence and Antimicrobial Sensitivity Pattern among Patients-A Multicenter Study in Asmara, Eritrea.

Background Methicillin-resistant Staphylococcus aureus (MRSA) is a well-recognized public health problem throughout the world. The evolution of new genetically distinct community-acquired and livestock-acquired MRSA and extended resistance to other non-β-lactams including vancomycin has only amplified the crisis. This paper presents data on the prevalence of MRSA and resistance pattern to other antibiotics on the selected specimen from two referral hospitals in Asmara, Eritrea. Method A cross-sectional study was conducted among 130 participants recruited from two referral hospitals in Asmara, Eritrea. Isolation of S. aureus was based on culture and biochemical profiles. Standard antimicrobial disks representing multiple drug classes were subsequently set for oxacillin, gentamicin, erythromycin, and vancomycin. Data were analyzed using SPSS version 20 software. Results S. aureus isolation rate from the 130 samples was 82 (63.1%). Patients <18 years of age were more likely to be colonized by S. aureus compared to patients above 61 years. The proportion of MRSA among the isolates was 59 (72%), methicillin-intermediate S. aureus (MISA) was 7 (8.5%), and methicillin-sensitive S. aureus (MSSA) was 15 (19.5%). The isolates were mostly from the pus specimen in burn, diabetic, and surgical wound patients. Antimicrobial susceptibility test showed that 13 (15.9%) of the isolates were resistant to vancomycin, 9 (11.0%) to erythromycin, and 1 (1.2%) to gentamicin. Coresistance of MRSA isolates to some commonly used antibiotics was also noted: oxacillin/erythromycin 5 (6.1%) and oxacillin/vancomycin 9 (11%). A few isolates were resistant to oxacillin/vancomycin/erythromycin 2 (2.4%) and oxacillin/gentamicin and erythromycin 1 (1.2%). Conclusion This study reports a relatively high prevalence of MRSA. Isolates that are resistant to other tested antibiotics including vancomycin are also reported. The data have important implication for quality of patients care in the two settings: antibiotic selection and infection control practices, and the need for additional studies.

Decrease of methicillin resistance in Staphylococcus aureus in nosocomial infections in Germany–a prospective analysis over 10 years

Methicillin resistant Staphylococcus aureus (MRSA) remains an important cause of healthcare-associated infections. Here, we describe the development of methicillin-resistant isolates among nosocomial Staphylococcus aureus (SA) infections in Germany between 2007 and 2016. We analyzed data from the voluntary German national nosocomial Infection Surveillance System. Data on bloodstream infections (BSI) and lower respiratory tract infections (LRTI) were derived from intensive care units (ICU), whereas data on surgical site infections (SSI) were collected from surgical departments (SD). Univariate analysis was performed on trend of proportion, while multivariable logistic regression was performed to identify risk factors for MRSA-infections. Data of 1218 ICU and 1,556 SD were included. Overall, a decrease in the proportion of MRSA among all nosocomial SA-infections from 32.8% to 20.0% was noted. MRSA decreased from 37.1% to 21.8% (p = 0.01) for BSI, from 38.7% to 19.2% for LTRI (p<0.01) and. from 21.1% to 7.4% (p<0.01) in SSI. Logistic regression revealed that SA-infections in Mecklenburg Western-Pomerania were more likely caused by MRSA (Odds ratio (OR): 2.5; 95% CI: 1.7, 3.6). We observed a significant reduction of the proportion of nosocomial Staphylococcus aureus infections due to MRSA in Germany over the course of the last 10 years.

Decreasing methicillin-resistant Staphylococcus aureus (MRSA) infections is attributable to the disappearance of predominant MRSA ST239 clones, Shanghai, 2008–2017

ABSTRACT A consistently decreasing prevalence of MRSA infections in China has been reported, however, the underlying mechanism of molecular processes responsible for this decline in MRSA infections has been poorly understood. We conducted an epidemiologic investigation to determine the dynamic changes of Staphylococcus aureus infections. A total of 3695 S. aureus isolates was recovered from 2008 to 2017, and subsequently characterized by infection types, resistance profile, and clone types. The frequency of respiratory infection decreased over the study period from 76% to 52%. The proportion of MRSA remarkably decreased (from 83.5% to 54.2%, 2008-2017) (p < .0001). The prevalence of predominant healthcare-associated MRSA (HA-MRSA) clones, ST239-t030 and ST239-t037, significantly decreased (from 20.3% to 1% and 18.4% to 0.5%, 2008-2017, respectively); both of them were replaced by the continually growing ST5-t2460 clone (from 0% to 17.3%, 2008-2017). Epidemic community-acquired MRSA (CA-MRSA) ST59 and ST398 clones also increased (from 1.0% to 5.8% and 1.8% to 10.5%, 2008-2017, respectively). These results demonstrated a significant decrease in the previously dominant HA-MRSA ST239 clones, leading to a marked decrease in the prevalence of MRSA over the past decade, and shed new light on the complex competition of S. aureus clones predominating within the health-care environment.

Using Core-genome Multilocus Sequence Typing to Monitor the Changing Epidemiology of Methicillin-resistant Staphylococcus aureus in a Teaching Hospital.

This study was performed to elucidate the changing epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in a Chinese teaching hospital. We performed whole-genome sequencing and phylogenetic analysis on MRSA isolates recovered at Sir Run Run Shaw Hospital (SRRSH) from 2013 to 2015. MRSA isolates underwent susceptibility testing, resistance determinant screening, virulence assays and clinical data analysis. A total of 292 MRSA infections were identified during the study period. Of these, most belonged to sequence type (ST) 5 (51.4%; 150 of 292) and ST59 (23.3%; 68 of 292). The proportion of ST5 MRSA decreased from 68.3% in 2013 to 32.1% in 2015, and the proportion of ST59 MRSA increased from 8.9% to 41.0%. Core-genome phylogenetic analysis revealed that ST59 MRSA isolates exhibited wider genotypic diversity than ST5 MRSA isolates in both healthcare-onset and community-onset groups. Minimum spanning trees showed that a cluster of ST5 MRSA was circulating at SRRSH, whereas the ST59 MRSA infections were mostly sporadic. ST59 MRSA caused 45.2% of the 93 skin and soft-tissue infection cases and displayed lower levofloxacin (11.8%) and ciprofloxacin (19.1%) resistance rates than the ST239 and ST5 MRSA isolates. ST59 healthcare-onset MRSA displayed enhanced virulence in the skin infection model and hemolysis assays. Notably, these isolates had virulence levels similar to those of classic community-associated MRSA strains. ST59 MRSA strains with high virulence potential have been replacing ST5 MRSA in predominance in SRRSH and causing nosocomial infections. Whole-genome sequencing is a powerful tool to monitor changes in the epidemiology of MRSA in hospitals.