Methicillin-resistant Staphylococcus Aureus Nasal Carriage Research Articles

COMPARISON OF NASAL CARRIAGE OF MRSA AND ITS ANTIBIOTIC SUSCEPTIBILITY WITH SPECIAL REFERENCE TO MUPIROCIN AMONG STUDENTS OF HEALTH-CARE SETTINGS AND OTHER STUDENTS

Objectives: One of the potential risk factors for nosocomial staphylococcal and Methicillin-resistant Staphylococcus aureus (MRSA) infections is colonization of the anterior nares of HCWs, and from there they may spread to the patients, which may cause a burden on the health-care system. In this context, we made an attempt to compare the Staphylococcal and MRSA nasal carriage and their susceptibility to Mupirocin in students who are exposed to the health-care system and those who are not. Methods: Nasal swabs were collected from 100 paramedical students as the study group and 100 non-medical students as the control group, all in the age group between 18 and 21 years. 5% sheep blood agar and mannitol salt agar were used to isolate S. aureus, and antibiotic sensitivity was done by Kirby Bauer Disc Diffusion Technique. Cefoxitin disc (30 μg) and Vancomycin screen agar were used to detect MRSA and Vancomycin resistance, respectively. A 5 μg disc of Mupirocin was used to test the susceptibility of Mupirocin. Results: Nasal carriage rate of S. aureus and MRSA was 23% and 8% in Paramedical students and 17% and 4% in Nonmedical students respectively. 83% of isolates from paraclinical students and 95% of isolates from non-medical students were susceptible to linezolid. Out of 12 MRSA strains from both groups only one strain showed resistance to Mupirocin. Conclusions: Nasal carriage of S. aureus and MRSA and antibiotic resistance of isolated strains were more common in paramedical students and also in female students. Vancomycin resistance was not observed in MRSA strains from male students. Mupirocin resistance, even in a single case, needs to be addressed.

Clinical Efficacy of Nasal Screening and Methicillin-Resistant Staphylococcusaureus Decolonization in Total Hip Arthroplasty without Chlorhexidine Soap or Vancomycin.

Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a known risk factor for periprosthetic joint infection (PJI). In our facility, preoperative prophylaxis with mupirocin without the chlorhexidine soap scrub or vancomycin was consistently implemented for more than 15years. This study aimed to evaluate the current screening and treatment of intranasal MRSA colonization in our elective primary THA patient population. All patients who underwent primary THA between April 2011, and March 2021 were included in this analysis. All patients were screened preoperatively for nasal MRSA approximately 1month before surgery. Patients with nasal MRSA contamination are treated with topical mupirocin to eradicate the bacteria before surgery. The patients were examined again approximately two weeks before surgery. We evaluated the current screening and treatment of intranasal colonization with MRSA in our elective primary total hip arthroplasty (THA) patient population. Out of 6251 patients, 106 (1.7%) had nasal MRSA contamination. The bacteria were not eradicated in three (3.6%) patients at the second screening. Twenty-two joints (0.35%) out of the 6251 had deep infections. Only 1 patient out of the 106 MRSA nasal carriers suffered from PJI. Twenty-one of the 6145 non-carriers had PJI. The difference between the prevalence of nasal MRSA contamination and the incidence of deep infections was not statistically significant. Our findings suggest that screening of all patients for nasal MRSA before THA followed by mupirocin calcium treatment if needed is sufficient PJI prophylaxis.

Antibiotic resistance and Staphylococcal super antigenic determinants in methicillin resistant Staphylococcus aureus isolated from anterior nares of dental students

Background: Staphylococcus aureus primarily inhabits the human anterior nares. Asymptomatic Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in healthcare professionals makes them potential MRSA reservoirs. Since identification and decolonization would promote cross-contamination reduction and curb communal transmission, this study was designed to identify MRSA nasal carriers among dental students and detect staphylococcal super antigenic determinants among them. Methods: Staphylococci isolates (n=52) from dental students(n=42) were investigated in the study. Following initial microbial speciation and antimicrobial susceptibility determination using standard identification methods, the MRSA strains were identified phenotypically using cefoxitin disc (30 µg). Genes encoding the virulence determinants, namely, TSST (test), enterotoxins (sea and seb), and cytotoxin (pvl), were looked for by PCR. Results: Only 15.09% of isolates were identified as Staphylococcus aureus, and all of them (n=8) were scored as MRSA using the cefoxitin disc diffusion method. None of the tested isolates showed the presence of virulence determinants in standard molecular techniques. Conclusion: Lower prevalence of S. aureus, MRSA, coupled with the absence of virulence determinants in the strains, suggests strategies for better surveillance. Tracking virulence-causing genes in nasal carrier S. aureus strains could enhance efforts to prevent infection outbreaks.

Nasal carriage of methicillin and inducible clindamycin resistant Staphylococcus aureus among healthcare workers in a tertiary care hospital, Kathmandu, Nepal

Introduction and Objectives: Transmission of methicillin-resistant Staphylococcus aureus (MRSA) from healthcare workers is one of the most frequent causes of nosocomial infections globally. There is a significant burden of nosocomial MRSA infections in low and low-middle income countries (LMICs), including Nepal. The present study investigated the rate of nasal carriage of MRSA among the healthcare workers in a tertiary care hospital, in Kathmandu, Nepal with emphasis on inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance. Material and method: The study was conducted at Star Hospital, Lalitpur, Nepal, from September 2022 to November 2022. Healthcare workers (HCWs) working at the diffeerent departments of the hospital were enrolled. Nasal swabs from both anterior nares of HCWs were collected aseptically and cultured on Mannitol Salt agar. S. aureus was identified by Gram stain and standard biochemical tests. Antibiotic susceptibility of S. aureus was performed by disc diffusion method. MRSA isolates were detected phenotypically by disc diffusion method using cefoxitin disc (30 µg), and inducible clindamycin resistance was detected phenotypically by the D-zone test. Results: Total 105 HCWs were enrolled in the study. Out of 105 HCWs, 14 (13.3%) were positive for S. aureus among which 6 (5.7%) were MRSA carriers. The nasal carriage of MRSA was highest among doctors (16.7%) and the HCWs of the post-operative department (14.3%). All the isolated MRSA were susceptible to chloramphenicol and vancomycin. Inducible MLSB resistance was detected in 33.3% MRSA while the rate was 21.4% in all isolated S. aureus. Conclusion: The study demonstrated that HCWs could be the potential source of nosocomial infection by methicillin and inducible clindamycin resistant S. aureus. Thus, preventive measures should be initiated to mitigate the risk of its spread and the test for detection of inducible clindamycin resistance should be incorporated into the routine antibiotic susceptibility testing in hospital settings. IMC J Med Sci. 2024; 18(1):005. DOI: https://doi.org/10.55010/imcjms.18.005 *Correspondence: Gaurab Pandey, Non-Communicable Disease Laboratory, National Public Health Laboratory, Teku, Kathmandu, 44600, Nepal; E-mail: pandeygaurab67@gmail.com

Association between methicillin-resistant Staphylococcus aureus nasal carriage and infection after pancreatic surgery.

Methicillin-resistant Staphylococcus aureus (MRSA) infections after pancreatectomy are relatively rare; however, they can be fatal when associated with pseudoaneurysms. For the past 12 years, we have been investigating nasal MRSA carriage by polymerase chain reaction testing, postoperatively in patients admitted to the intensive care units, to prevent nosocomial infections. Here, we investigated the relationship between MRSA nasal carriage and postoperative MRSA infection at the surgical site, following pancreatectomy. This single-center retrospective study analyzed 313 pancreatectomies (220 pancreaticoduodenectomies and 93 distal pancreatectomies), performed at our hospital between January 2011 and June 2022. The incidence of surgical site infection (SSI) and postoperative MRSA infection were compared between the nasal MRSA-positive and nasal MRSA-negative groups. MRSA nasal carriage was identified in 24 cases (7.6%), and the frequency of SSIs in the nasal MRSA-positive and MRSA-negative groups were 50% and 36.7%, respectively, with no significant difference (p = .273). However, the frequency of MRSA infection among the SSI cases was significantly higher in the nasal MRSA-positive group (16.7%) than in the nasal MRSA-negative group (1.7%) (p = .003). It should be noted that MRSA carriers have a significantly higher frequency of MRSA-positive SSIs.

Prevalence study of methicillin resistant <i>Staphylococcus aureus</i> and its SCC<i>mec</i> features in horses and handlers in Zaria and Kaduna, Nigeria

Methicillin resistant Staphylococcus aureus (MRSA) is a pathogen with public health implications being resistant to most used antibiotics. It has been associated with health facilities but has now become prevalent in community settings. The presence of MRSA in 240 apparently healthy horses and 65 horse handlers in Kaduna and Zaria was studied through nasal swabs collection by a one-stage cluster sampling and analysed using standard microbiological tests and genotyping methods. Questionnaires were also administered to assess for risk factors associated with MRSA carriage. Prevalence was 10% and 6.2% from the horses and horse handlers respectively. The S. aureus isolates showed highest resistance rates of 54.6% to penicillin and oxacillin. There were high resistance rates also to erythromycin, and tetracycline of 47.7% and 34.1% respectively. Resistance of 22.7% to amikacin and gentamicin, 6.8% to sulphamethoxazole+trimethoprim, 2.3% to ciprofloxacin, and 2.3% to chloramphenicol were also observed. Multidrug resistance (MDR) was found among 74.8% of the MRSA isolates. SCCmec typing showed types I, III, and IV in both the horses and the horse handlers while one horse was found to carry SCCmec V. Possible risk factors identified for MRSA carriage by horse handlers included being a veterinarian, exposure to antimicrobial agents, healthcare facility visitation, and personal hygiene. For the horses, risk factors from this study were allergy and wound management. MRSA nasal carriage in horses and horse handlers, as well as MDR (multidrug resistant) strains of S. aureus have been established from this study, this is of public health concern.

SCREENING OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AMONG HEALTHCARE WORKERS AND THEIR ANTIBIOTIC SUSCEPTIBILITY PATTERN IN A TERTIARY CARE HOSPITAL

Objective: Colonization of Staphylococcus aureus in the nasal flora has been proven to play an important role in the transmission of infections. Health care workers carrying Staphylococcus aureus in their nose or skin play an important role in cross-contamination and thus result in Methicillin-resistant Staphylococcus aureus (MRSA) related hospital-acquired or community-acquired infections. Implementation of hand hygiene methods and standard precautions are helpful in reducing transmission and controlling spread. Screening for carriage of MRSA is fundamental step in nosocomial infection control. The present study was undertaken to determine the prevalence of MRSA carriage rate and study their antibiogram.
 Methods: A cross-sectional study was conducted for a period of six months and samples from 185 HCWs working in high-risk areas were processed by standard protocols. As per CLSI guidelines, MRSA detection by disc diffusion method using Cefoxitin disc (30μg) and further determined by Epsilometer test (E-test) by interpreting Minimum inhibitory concentration (MIC) values (mcg/ml).
 Results: Out of 185 nasal swabs, 53 were Staphylococcus aureus isolates. MRSA colonization is seen in (8.64%) samples. Preponderance was seen in staff nurses (10.16%). Antibiogram of MRSA isolates showed sensitivity to Vancomycin and linezolid.
 Conclusion: The present study was undertaken to screen nasal carriage of MRSA among healthcare workers, as they pose a potential risk factor for nosocomial transmission leading to MRSA outbreaks. The strengthening of Infection prevention and control measures institutionalization of antimicrobial stewardship programs helps in curbing the spread of MRSA.

Pilot study on nasal microbiota dynamics and MRSA carriage of a pig cohort housed on straw bedding.

Methicillin-resistant Staphylococcus aureus (MRSA) can be transmitted between pigs and humans on farms. Hence, the reduction of MRSA carriage in pigs could decrease the risk of zoonotic transmission. Recently, straw bedding has been found to significantly reduce MRSA carriage in pigs. The mechanisms behind this effect remain unclear but changes in the nasal microbiome may play a role. In this exploratory study, the nasal microbiota of pigs kept on straw was examined using V1/V2 16S rRNA gene sequencing. Nasal swabs were collected from 13 pigs at six different time points during the course of a full fattening cycle resulting in 74 porcine samples. In addition, straw samples were collected at each time point. Eleven out of 13 pigs were MRSA positive at housing-in. We found a strong temporal pattern in the microbial communities. Both microbial diversity and abundance of Staphylococcus species peaked in week 5 after introduction to the straw stable decreased in week 10, when all pigs turned MRSA-negative, and increased again toward the end of the fattening period. These findings show that the introduction of pigs into a new environment has a huge impact on their nasal microbiota, which might lead to unfavorable conditions for MRSA. Moreover, other Staphylococcus species may play a role in eliminating MRSA carriage. We designed a follow-up study including two different husbandry systems to further assess these effects.

Molecular characterization and antimicrobial resistance of nasal Staphylococcus aureus in the community of Kabul

This study aimed to investigate the prevalence and molecular characteristics of community methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage among students at Kabul University. Nasal swabs were collected from anterior nares of 150 healthy non-medical students at Kabul University. Antimicrobial susceptibility testing was performed on all S. aureus isolates, and all detected MRSA isolates were then confirmed by mecA/mecC polymerase chain reaction and characterized using DNA microarray. A total of 50 S. aureus strains were isolated from the anterior nares of the 150 participants. The prevalence of S. aureus and MRSA nasal carriage among Kabul students was 33.3% and 12.7%, respectively. Seven (36.8%) MRSA isolates and 8 (25.8%) methicillin-susceptible S. aureus (MSSA) isolates were multidrug-resistant (i.e. resistant to at least three different antimicrobials tested). All MRSA isolates (n=19) were susceptible to linezolid, rifampicin, and fusidic acid. Seven MRSA clones, belonging to four clonal complexes (CCs), were identified. The most commonly identified clone was CC22-MRSA-IV TSST-1-positive, which accounted for 63.2% (12/19) of MRSA isolates. SCCmec typing showed that most MRSA strains harboured SCCmec type IV (94.7%). Thirteen (68.4%) MRSA isolates carried the TSST-1 and 5 (26.3%) PVL genes. Our findings revealed the relatively high prevalence of MRSA nasal carriers in the community in Kabul, with the predominance of the CC22-MRSA-IV TSST-1-positive clone and frequent multidrug resistance among these isolates.

Prevalence of nasal colonization by methicillin-resistant Staphylococcus aureus in medical students in Chile: comparison between pre-clinical and clinical environment

The primary objective of this study was to determine the prevalence of nasal colonization of methicillin resistant Staphylococcus aureus (MRSA) in medical students in pre-clinical versus clinical courses at the Pontificia Universidad Católica de Chile and to describe the epidemiological, clinical and molecular pattern of the MRSA strains obtained. A cross-sectional descriptive study was carried out on 299 undergraduate and graduate medical students from the Pontificia Universidad Católica de Chile, 44 first-year students and 29 second-year students, corresponding to students of courses without regular clinical exposure and 26 sixth-year students, 58 seventh-year and 142 residents, who are daily exposed to hospital environments. A carriage of 0% (0/73) was found in students not exposed to the clinic (pre-clinical courses) and 0.9% (2/226) in students of clinical courses, a difference that was not statistically significant (p-value 0.42). The MRSA nasal carriage found in our medical students was low, finding positive samples only in students with clinical exposure. This prevalence is similar to the one reported in other studies in Chile with similar characteristics.

The Emergence of Mupirocin Resistance among Staphylococcus aureus in a Tertiary Care Hospital in South India: The Necessity for Routine Susceptibility Testing

Methicillin-resistant Staphylococcus aureus (MRSA) is difficult to treat, causing considerable morbidity and mortality. Nasal carriage of MRSA can occur both in healthcare workers and patients. Mupirocin is used as a topical agent for the eradication of such isolates. The present study aims to study the prevalence of mupirocin resistance among the MRSA and MSSA (Methicillin-sensitive Staphylococcus aureus) isolates. A total of 148 Staphylococcus aureus isolates were tested. Antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method for amoxicillin, penicillin, cotrimoxazole, clindamycin, mupirocin(5 µg and 200 µg discs for low and high-level resistance), erythromycin, gentamicin and linezolid. MRSA isolates were detected by cefoxitin disc diffusion and Mec A detection by PCR (Polymerase Chain Reaction). MRSA was detected among 44 (29.7%) of the isolates. Among MSSA, good susceptibility was observed for cotrimoxazole 89 (85.5%) and clindamycin 92 (88.4%). An overall mupirocin resistance of 12(8.1%) was observed, with high-level resistance at 4 (2.7%) and low-level resistance at 8 (5.4%).The mupirocin resistance pattern between MRSA and MSSA was not statistically significant (p=0.1833). The emergence of mupirocin resistance highlights the necessity for creating cognizance among clinicians before prescribing mupirocin. In eradicating nasal carriage of MRSA, all the isolates should always be tested for mupirocin susceptibility to prevent the selection and spread of drug-resistant isolates.

Methicillin-resistant Staphylococcus aureus nasal carriage among patients on haemodialysis with newly inserted central venous catheters.

Although methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization is common among end-stage kidney disease patients undergoing haemodialysis, few studies were focused on MRSA nasal carriers among haemodialysis patients with central venous catheters (CVCs). The aim of this study is to evaluate the risk factors, various clinical outcomes and effect of decolonization for MRSA nasal colonization among patients on haemodialysis via CVCs. This was a single-centre non-concurrent cohort study of 676 patients who had new haemodialysis CVCs inserted. They were all screened for MRSA colonization via nasal swabs and were categorized into two groups: MRSA carriers and MRSA noncarriers. Potential risk factors and clinical outcomes were analysed in both groups. All MRSA carriers were given decolonization therapy and the effect of decolonization on subsequent MRSA infection was also performed. Eighty-two patients (12.1%) were MRSA carriers. Multivariate analysis showed that MRSA carrier (OR 5.44; 95% CI 3.02-9.79), long-term care facility resident (OR 4.08; 95% CI 2.07-8.05), history of Staphylococcus aureus infection (OR 3.20; 95% CI 1.42-7.20) and CVC in situ > 21days (OR 2.12; 95% CI 1.15-3.93) were independent risk factors for MRSA infection. There was no significant difference in all-cause mortality between MRSA carriers and noncarriers. The MRSA infection rates were similar between MRSA carriers with successful decolonization and those who had failed/incomplete decolonization in our subgroup analysis. MRSA nasal colonization is an important cause of MRSA infection among haemodialysis patients with CVCs. However, decolonization therapy may not be effective in reducing MRSA infection.

Evaluating Methicillin-Resistant Staphylococcus aureus Polymerase Chain Reaction Nasal Screening as a Tool for Antimicrobial Stewardship

IntroductionInitiation of broad-spectrum empiric antibiotics is common when infection is suspected in hospitalized adults. The benefits of early utilization of effective antibiotics are well documented. However, the negative effects of inappropriate antibiotic use have led to antimicrobial stewardship mandates. Recent data demonstrate the utility of methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) nasal screening to steward anti-MRSA empiric antibiotics in pneumonia. We hypothesize that MRSA PCR nasal swabs would also be effective to rule out other MRSA infection to effectively limit unnecessary antibiotics for any infectious source. MethodsWe performed a single-center retrospective chart review of all adult patient encounters from October 2019-July 2021 with MRSA PCR nasal testing. We then reviewed all charts to evaluate for the presence of infections based on source cultures results, as the gold standard. Sensitivity, specificity, negative predictive value, and positive predictive value were calculated from 2 × 2 contingency tables. ResultsAmong all patients with MRSA nasal screening, 1189 patients had any infection. Prevalence of MRSA nasal carriage among patients screened was 12%. Prevalence of MRSA infection among all infections was 7.5%. MRSA nasal swabs demonstrated a negative predictive value of 100% for MRSA urinary tract infection, 97.9% for MRSA bacteremia, 97.8% for MRSA pneumonia, 92.1% for MRSA wound infection, and 96.6% for other MRSA infections. Overall, MRSA PCR nasal swabs had a sensitivity of 68.5%, specificity of 90.1%, positive predictive value of 23.7%, and negative predictive value of 98.5% for any infections. ConclusionsMRSA PCR nasal swabs have a high negative predictive value for all infections. Our data support the use of MRSA PCR nasal swabs to rule out MRSA infection and thereby allow early de-escalation of MRSA coverage in hospitalized patients requiring empiric antibiotics. Implementation of MRSA screening could decrease antibiotic-associated morbidity, resistance, and costs. More studies should be conducted to validate these results and support these findings.

EPIDEMIOLOGICAL TOOL IN THE STUDY OF MRSA NASAL CARRIAGE AMONG HEALTH CARE WORKERS OF TERITARY CARE HOSPITAL - ITS UTILITY

Background And Objectives: Staphylococcus aureus is a common cause of community and hospital acquired infections. Methicillin resistant Staphylococcus aureus (MRSA) is a common nosocomial pathogen in the ICUs and other parts of the hospital and presents a challenge for all health care institutions. One of the important sources of MRSA in hospital setting is nasal carriage among health care workers (HCW's). Thus screening of health care workers for MRSA carriage will be helpful in preventing spread of MRSA from colonized health care workers to patients. The objective of the study is to to estimate the prevalence of nasal carriage of MRSA among health care workers of our institution. It is a prospective study done at Institute of Microbiology, Madurai Materials And Methods: Medical College, Madurai with the study period of two months. Nasal swabs collected from 100 healthcare workers working in different departments of our tertiary care hospital. All the swabs were inoculated on to Mannitol salt agar plates and incubated at 37°c for 24hrs to isolate Staphylococcus aureus. MRSA strains were identied by disc diffusion method using Cefoxitin (30฀g) disc. Results: Out of 100 HCWs, 21 (21%) were nasal carriers of S.aureus and among them 2(2/21) (9.5%) were carrier of MRSA. The overall nasal carriage rate of MRSA was 2%(2/100). S. aureus carriage rate was highest among Staff nurses 27.7 % (5/18) while MRSA carriage rate was highest among Interns 3.3%(1/30). In our study, nasal Conclusion: carriage of MRSA among the health care workers is 2 % with the rate being highest among Interns. Considering the fact that Health Care Workers are more involved in the patient care activities, it is necessary to sensitize them regarding this issue and we should emphasize the importance of hand washing on them.

Methicillin resistance Staphylococcus aureus nasal carriage and its associated factors among HIV patients attending art clinic at Dessie comprehensive specialized hospital, Dessie, North East Ethiopia.

Globally the incidence of nosocomial infections and colonization due to methicillin resistant Staphylococcus aureus (MRSA) has become greater concern. The objective of the study was to determine the prevalence and associated factors of nasal carriage of MRSA with its antimicrobial susceptibility patter among HIV patients attending ART clinic. cross-sectional study was conducted from January 01 to May 30, 2020 at Dessie comprehensive specialized hospital, north east Ethiopia. A total of 206 HIV patients were recruited by applying systematic random sampling technique. Nasal specimen was collected from both anterior nares, and inoculated directly on mannitol salt agar, MacConkey, 5% blood agar. Screening of MRSA and methicillin susceptible Staphylococcus aureus (MSSA) strain was done by using cefoxitin antibiotic disc following modified Kirby-Bauer disc diffusion technique. Bivariable and multivariable logistic regression analyses were performed to assess the associated factors with S. aureus and MRSA. study participants were in the age range between 12 and 72 years and their mean (±SD) age was 41.52 (±11.2). The rate of S. aureus and MRSA colonization was 127/206 (61.7%) and 58/206 (28.2%), respectively. Having job close contact with human [AOR = 4.41; 95% CI = 1.5-13.02; p = 0.007], picking the nose [AOR = 4.38; 95% CI = 1.34-14.29; p = 0.014] and ART failure [AOR = 7.41; 95% CI = 2.08-26.41; p = 0.002] had statistically significant association with MRSA colonization. MRSA showed resistance for tetracycline (53.4%), erythromycin (84.5%), and trimethoprim-sulfamethoxazole (86.2%). Multi-Drug Resistance (MDR) was detected among 96.5% of MRSA and 20.3% of MSSA isolates. the rate of S. aureus and MRSA nasal colonization was high and it has associated with different factors. Understanding and managing MRSA among HIV patients is mandatory and stakeholders should find out the way how to decolonize the bacteria from nasal area.

Methicillin-resistant Staphylococcus aureus nasal colonization in people living with HIV and healthypeople in Kathmandu, Nepal.

Aim:This study aimed to compare methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization in people living with HIV (PLHIV) and healthy people from Kathmandu.Methods:MRSA isolated from 400 nasal swabs was screened using a cefoxitin disc and confirmed by the presence of the mecA gene.Results:MRSA nasal carriers among the PLHIV and control cohorts were 3.5% (7 out of 200) and 5.0% (10 out of 200), respectively. All the MRSA from PLHIV and most of MRSA from healthy controls were PVL positive. Longer duration of antiretroviral therapy significantly reduces the risk of MRSA nasal colonization in PLHIV.Conclusion:There is no significant difference in MRSA nasal colonization in PLHIV and healthy controls in this study region.

Molecular Typing of Community-acquired Methicillin-Resistant Staphylococcus aureus Isolated from 2- to 6-year old Children by Staphylococcal Protein A and Agr Typing in Isfahan, Iran.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has become a considerable public health concern in the entire world due to the rapid spread of this bacterium in human community; also the epidemiology of MRSA has changed, as the isolation of MRSA strains from healthy and non-healthy patients. Therefore, the objective of this study is to determine the genetic diversity and antibiotic resistance profile of community-acquired (CA)-MRSA nasal carriage in the Iranian samples.Materials and Methods:A total of 25 CA-MRSA were isolated from the anterior nares of 410 healthy preschool children. All MRSA isolates were characterized by the detection of the toxic shock syndrome toxin-1 (TSST-1) and typed by γ-hemolysin genes, agr groups, and staphylococcal protein A (spa) typing. Kirby-Buyer antibiotic susceptibility testing was performed and interpreted as per the standard guidelines.Results:A total of 25 (6.1%) MRSA isolates were recovered from the anterior nares of 410 preschool children. Sixteen isolates (64%) were positive for the TSST-1 gene. Three agr specificity groups were determined, as follows: eight (32%) isolates belonged to agr Group I, five (20%) isolates belonged to agr Group II, and 12 (48%) isolates belonged to agr Group III. The repeated profiles of these spa types of 25 isolates were organized into eight different lineages groups. Five of lineages contained a single strain, three of lineages contained two strains, and three of lineages consisted of more than three strains.Conclusions:The results of our study show that the rate of MRSA in our region is significantly high. Additionally, spa type t037 was the predominant type among CA S. aureus.

English

Methicillin-resistant Staphylococcus aureus (MRSA) is a major hospital acquired pathogen. In Cameroon, there is limited data on nasal carriage of MRSA and its antibiotic susceptibility testing and risk factors for multi resistance to antibiotics in hospitalized patients and medical staff . A prospective, qualitative, cross-sectional hospital-based study was carried out. Anterior nasal swabs were taken from 579 participants and bacterial strains were identified by conventional method and antibiotic susceptibility testing. Methicillin resistance was confirmed with cefoxitin and oxacillin disks. Of the 579 samples analysed, 53.0% were positive for S. aureus, 45.4% were MRSA. MRSA constituted 85.7% of all the S. aureus identified. The prevalence of MRSA in nasal carriage was significantly higher in females (49.6%) than in males (34.0%). The overall prevalence of MRSA in nasal carriage in both medical staff and hospitalized patients was 45.4%. The prevalence of MRSA in nasal carriage was significantly higher in RHL (49.0%) and RHB (48.5%) compared to the UTHY (36.3%). The prevalence of MRSA in nasal carriage was significantly higher in the surgical ward (59.7%) and paediatric ward (45.2%) compared to the other units. Among the MRSA isolates, the maximum sensitivity was observed with vancomycin (97.0%) and minocycline (95.1%), while the least sensitivity was observed with penicillin (0.0%) and ampicillin (0.8%). Binary logistic regression model showed that being aged 35 years an above and being hospitalized for more than 15 days were strongly associated with MDR to MRSA. Nasal carriage of MRSA is increasing rapidly and call for urgent preventive measures. Key words: Healthcare personnel, adult patients, nasal carriage, antibiotic susceptibility, risk factors, health care personnel, adult, patients, multi drug resistance (MDR), methicillin-resistant Staphylococcus aureus (MRSA).

Nasal carriage of methicillin resistant Staphylococcus aureus among medical students of a private institution in Ilishan-Remo, Ogun State, Nigeria

Background: Nasal carriage of methicillin resistant Staphylococcus aureus (MRSA) is a major factor for its transmission especially from the health workers and medical students to their patients. There are a number of published data on the prevalence of MRSA among health workers but data on nasal colonization of medical students by MRSA are sparse in Nigeria. The objectives of this study are to determine the prevalence of nasal carriage of MRSA among medical students of the Ben Carson School of Medicine, Babcock University, Ilishan-Remo, Ogun State, Nigeria, and identify risk factors associated with this nasal carriage.
 Methodology: A case control study involving 100 clinical (study group) and 100 pre- clinical (control group) medical students was undertaken between March 2018 and October 2019. Structured questionnaire was administered to obtain socio-demographic information and potential risk factors. Nasal swab was collected from each student and cultured for isolation of S. aureus by standard microbiology techniques. Phenotypic MRSA was detected by the cefoxitin 30μg disk diffusion method according to the guideline of Clinical and Laboratory Standards Institute. The mecA gene was detected by conventional polymerase chain reaction (PCR) assay.
 Results: The prevalence of S. aureus nasal carriage among the study group was 14% (14/100) while the prevalence among the control group was 6% (6/100) (p=0.097). The prevalence of phenotypic MRSA among the study group was 4% (4/100) and 1% (1/100) among the control group (p=0.3687) while mecA gene was detected in 3 of the 4 (75%) phenotypic MRSA positive study participants and in the only (100%) phenotypic MRSA positive (1%) control group. Antibiotics usage without prescription, antibiotic treatment of common cold, and use of antibiotics in the previous one year, were significantly associated with MRSA carriage among the study group.
 Conclusion: Although the prevalence of nasal carriage of S. aureus and MRSA among clinical and pre-clinical medical students was not statistically significant, the risk factors identified with carriage of MRSA among the study group indicates the need for antimicrobial stewardship program to reduce carriage and transmission of MRSA by medical students.
 Keywords: methicillin resistant, Staphylococcus aureus, mecA gene, nasal carriage, medical students

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among undocumented migrants and uninsured legal residents in Amsterdam, the Netherlands: a cross-sectional study

BackgroundNasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increased risk of infection. Colonization with MRSA is observed in < 1% of the general Dutch population. Increased risk for MRSA carriage is known to occur in several key groups, one of which is asylum seekers. However, little is known about MRSA carriage among undocumented migrants and uninsured legal residents. This study aimed to determine the prevalence of nasal MRSA carriage among these groups in Amsterdam, the Netherlands.MethodsIn this cross-sectional study, between October 2018 and October 2019, undocumented migrants and uninsured legal residents aged 18 years or older who were able to understand one of the study languages were recruited at an NGO health care facility in Amsterdam, the Netherlands, for general practitioner (GP) consultations. Participants were asked questions on demographics, migration history, antibiotic use and other possible risk factors for MRSA carriage and were screened for nasal MRSA carriage by selective culturing e-swabs. Characteristics of MRSA-negative and MRSA-positive participants were compared using univariable logistic regression analysis with Firth’s correction.ResultsOf the 3822 eligible patients, 760 were screened for nasal MRSA carriage (19.9%). Of the 760 participants, over half were male (58%; 442/760) and originated mainly from Africa (35%; 267/760), Asia (30%; 229/760) and North or South America (30%; 227/760). In total, 705/760 participants (93%) were undocumented migrants and 55/760 (7%) were uninsured legal residents of Amsterdam. The overall prevalence of nasal MRSA carriage was 2.0% (15/760) (95%CI 1.1 to 3.2%), with no difference between undocumented migrants (14/705) (2.0, 95%CI 1.1 to 3.3%) and uninsured legal residents (1/55) (1.8, 95%CI 0.1 to 9.7%). Genotyping showed no clustering of the 15 isolates. MRSA carriage was not associated with sociodemographic, migration history or other possible risk factors. Nevertheless, this study had limited power to detect significant determinants. Three participants (3/15; 20%) harbored Panton-Valentine leukocidin (PVL)-positive isolates.ConclusionEven though our study population of undocumented migrants and uninsured legal residents had a higher prevalence of nasal MRSA carriage compared to the general Dutch population, the prevalence was relatively low compared to acknowledged other high-risk groups.