Risk factors assessment for nasal colonization of Staphylococcus aureus and its methicillin resistant strains among pre-clinical medical students of Nepal

Assessment of Antibiotic Resistance in Pediatric Infections: A Romanian Case Study on Pathogen Prevalence and Effective Treatments

Antibiotic misuse in Romania has exacerbated the issue of antibiotic resistance, as patients often use antibiotics without proper medical consultation. This study aimed to assess the resistance of prevalent bacteria to different antibiotics. In this observational study conducted over six months, we analyzed 31 pediatric patients aged from 12 days to 13 years using the disk diffusion method. We identified 31 bacterial isolates, including 8 Gram-negative and 8 Gram-positive strains, with the most common being Pseudomonas aeruginosa, Escherichia coli, Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, Streptococcus species, and Elizabethkingia meningoseptica. Our findings revealed that the most effective antibiotics were linezolid, ertapenem, and teicoplanin. In contrast, nearly all tested bacteria exhibited resistance to penicillin, followed by oxacillin and ampicillin. Resistance to cephalosporins varied with generation, showing higher resistance to lower-generation cephalosporins. The study highlights significant antibiotic resistance among common bacterial pathogens in Romanian pediatric patients, emphasizing the urgent need for controlled antibiotic use and alternative treatment strategies to combat this growing issue. Effective antibiotics such as linezolid and ertapenem offer potential solutions, whereas reliance on penicillin and lower-generation cephalosporins is increasingly futile.

Recent development and fighting strategies for lincosamide antibiotic resistance

SUMMARYLincosamides constitute an important class of antibiotics used against a wide range of pathogens, including methicillin-resistant Staphylococcus aureus. However, due to the misuse of lincosamide and co-selection pressure, the resistance to lincosamide has become a serious concern. It is urgently needed to carefully understand the phenomenon and mechanism of lincosamide resistance to effectively prevent and control lincosamide resistance. To date, six mobile lincosamide resistance classes, including lnu, cfr, erm, vga, lsa, and sal, have been identified. These lincosamide resistance genes are frequently found on mobile genetic elements (MGEs), such as plasmids, transposons, integrative and conjugative elements, genomic islands, and prophages. Additionally, MGEs harbor the genes that confer resistance not only to antimicrobial agents of other classes but also to metals and biocides. The ultimate purpose of discovering and summarizing bacterial resistance is to prevent, control, and combat resistance effectively. This review highlights four promising strategies, including chemical modification of antibiotics, the development of antimicrobial peptides, the initiation of bacterial self-destruct program, and antimicrobial stewardship, to fight against resistance and safeguard global health.

Nasal carriage rate, associated factors, and antimicrobial susceptibility patterns of methicillin resistance Staphylococcus aureus among pre-clinical undergraduate students at the College of Health and Medical Sciences, Haramaya University, Ethiopia

Background

Staphylococcus aureus nasal carriage has been linked to higher rates of infection and morbidity. People with Methicillin-resistant Staphylococcus aureus can be a potential source of infection for others. University students living together in crowded conditions increase their risk of acquiring infections. The prevalence of S. aureus, particularly Methicillin-resistant Staphylococcus aureus nasal carriage, in Ethiopian university students is sparse.

Objective

This study aimed to determine the nasal carriage rate, associated factors, and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus among pre-clinical students at the College of Health and Medical Sciences, Haramaya University, Ethiopia, from 1 July to 30 August 2022.

Methods

An institutional-based cross-sectional study was conducted among 270 randomly selected pre-clinical Health and Medical Sciences students. Data on associated factors were collected using pre-tested, structured questionnaires. A nasal swab was taken from each participant and sent to the microbiology laboratory via Amies transport media in a cold chain. There, it was cultivated using conventional techniques. The isolated colonies were found to be S. aureus, and its antimicrobial susceptibility was performed using the Kirby-Bauer disk diffusion method on Muller-Hinton agar. Methicillin-resistant Staphylococcus aureus expressing using cefoxitin based on CLSI breakpoint. Data were entered into Epi-Data version 4.4.2.1 and exported to the Statistical Package for Social Sciences (SPSS) software version 25 for analysis. Pearson's chi-square test was performed to predict the associations between variables. A p-value less than 0.05 was regarded as statistically significant.

Result

Methicillin-resistant Staphylococcus aureus nasal carriage was 5.9% (95% CI: 3.09-8.7) of cases of S. aureus nasal colonization, which was found to be 12.96% (95% CI: 8.85-16.96). Methicillin-resistant Staphylococcus aureus nasal colonization was significantly associated with the history of cigarette smoking (p = 0.000), intake of khat (p = 0.042), nose-picking habit (p = 0.003), history of sharing personal goods (p = 0.021), and history of hospitalizations (p = 0.00). All of the Methicillin-resistant Staphylococcus aureus isolates were resistant to ampicillin and cefoxitin.

Conclusion

Based on the findings, a considerable proportion of healthy students harbored Methicillin-resistant Staphylococcus aureus strains associated with behavioral factors. Furthermore, these isolates showed high resistance to cefoxitin and ampicillin. Hence, it is crucial to regularly test pre-clinical students to prevent endogenous infections and the spread of Methicillin-resistant Staphylococcus aureus.

High Frequency of Methicillin-Resistant and Multidrug-Resistant Strains of Staphylococcus aureus Colonizing Students in Okada, Edo State, Nigeria

Staphylococcus aureus is one of the most common bacterial pathogens, often asymptomatically colonizing healthy people, but capable of causing fatal disease. The ability to treat S. aureus infections is limited by the rapid spread of multidrug-resistant strains. This study aimed to determine the prevalence of S. aureus carriage among students from Okada, Edo State, Nigeria, to analyze the antibiotic resistance patterns and molecular characteristics of S. aureus isolates. One hundred healthy students from Okada, Nigeria, were tested for nasal colonization by S. aureus. Isolates were identified using standard microbiological methods. The susceptibilities of the isolates to a panel of 22 antimicrobials were tested. spa and staphylococcal cassette chromosome mec typing were performed. The prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) among the students was 23% and 6%, respectively. Of the six (26.1%; 6/23) MRSA isolates detected, CC88-MRSA-IVa (n = 2) and CC7-MRSA-V (n = 2) were the most frequent clones. The CC7-MRSA-V isolates were resistant to multiple antimicrobials. Overall, resistance to beta-lactams, tetracyclines, fluoroquinolones, and aminoglycosides was detected among the S. aureus and MRSA isolates. The high prevalence of MRSA and methicillin-susceptible isolates with resistance to multiple antimicrobial classes observed among the students is an alarming finding. This study indicated the circulation of resistant clones of S. aureus in Nigerian educational institutions and the community.

Study of Phenotypic and Genotypic Factors of Staphylococcus aureus Clinical Local Isolates

The isolates of Staphylococcus aureus were isolated from patients with various infections in hospitals, the isolates were identified and accurately diagnosed by phenotypic examination and biochemical tests, as well Vitek-2, and then genetic detection and diagnosis of many of the pathogenic factors associated with Staphylococcus aureus using conventional polymerase chain reaction (PCR) and testing for association by antibiotic resistance and production of some toxins by Staphylococcus aureus. After performing analysis of statistical, it was set up that the correlation coefficient of the PCR technique using virulence genes, sensitivity test to antibiotics and other virulence factors were significant at p < 0.05, but was insignificant with the biofilm production.

Alhoot M, Abdul Karim S. Multidrug-Resistant Staphylococcus aureus as Coloniser in Healthy Individuals

Staphylococcus aureus is a common human pathogen that can cause mild superficial infections to deep-seated abscesses and sepsis. One of the characteristics of S. aureus is the ability to colonise healthy individuals while leaving them asymptomatic. These carriers’ risk harbouring an antibiotic-resistant strain that may be harmful to the individual and the community. S. aureus carriage in healthcare personnel is being studied extensively in many parts of the world. However, the relationship between colonisation and disease among those with no previous exposure to healthcare remains untouched. Colonisation of the nasal cavity and its surrounding by pathogenic organisms such as S. aureus leads to the increased risk of infection. Hospital-acquired infections associated with S. aureus infections are common and studies related to these types of infections among various study groups are largely documented. However, over the last decade, an increase in community-associated methicillin-resistant S. aureus has been noted, increasing the need to identify the prevalence of the organism among healthy individuals and assessing the antibiotic resistance patterns. Systemic surveillance of the community for colonisation of S. aureus and identifying the antibiotic-resistant pattern is critical to determine the appropriate empiric antibiotic treatment.

Antimicrobial resistance pattern of methicillin-resistant Staphylococcus aureus isolated from sheep and humans in Veterinary Hospital Maiduguri, Nigeria

Background and Aim: Methicillin-resistant Staphylococcus aureus (MRSA), an important opportunistic pathogen, is a Gram-positive coccus known to be resistant to β-lactam antibiotics. Its virulence depends on a large range of factors, mainly extracellular proteins, such as enzymes and exotoxins, that contribute to causing a wide range of diseases in human and animal species. The major reasons for the success of this pathogen are its great variability, which enables it to occur and thrive at different periods and places with diverse clonal types and antibiotic resistance patterns within regions and countries. Infections caused by antibiotic-resistant S. aureus bring about serious problems in the general population (humans and animals). Infections with these pathogens can be devastating, particularly for the very young, adults and immunocompromised patients in both humans and animals. This study aimed to determine the presence of MRSA in both apparently healthy and sick sheep brought to the veterinary hospital as well as veterinary staff and students on clinical attachment in the hospital. Materials and Methods: A total of 200 nasal swab samples were collected aseptically from sheep and humans (100 each) for the isolation of MRSA. The samples were processed by appropriately transporting them to the laboratory, then propagated in nutrient broth at 37°C for 24 h followed by subculturing on mannitol salt agar at 37°C for 24 h, to identify S. aureus. This was followed by biochemical tests (catalase and coagulase tests) and Gram staining. MRSA was isolated using Clinical Laboratory Standard Institute (CLSI) guideline and confirmed by plating onto Oxacillin (OX) Resistance Screening Agar Base agar. The antimicrobial susceptibility pattern of the MRSA isolates was determined using the disk diffusion method against 12 commonly used antimicrobial agents. Results: The total rate of nasal carriage of S. aureus and MRSA was found to be 51% and 43% in sheep and humans, respectively. The MRSA prevalence in male and female sheep was 18% and 8%, while 9% and 8% were for male and female human samples, respectively. The antimicrobial susceptibility test showed 100% resistance to OX, cefoxitin, oxytetracycline, cephazolin, and penicillin-G (Pen) by MRSA isolates from humans. Conversely, there was 100% susceptibility to ciprofloxacin, imipenem, and gentamicin; for linezolid (LZD), it was 87.5%, norfloxacin (NOR) (71%), and erythromycin (ERY) (50%) susceptibility was recorded. The MRSA isolates from sheep recorded 100% resistance to the same set of drugs used for human MRSA isolates and were equally 100% susceptible to gentamicin, imipenem, LZD, ciprofloxacin, NOR (92%), and ERY (50%). Conclusion: This study determined the presence of MRSA in sheep and humans from the Veterinary Hospital, Maiduguri. It appears that certain drugs such as ciprofloxacin, imipenem, and gentamicin will continue to remain effective against MRSA associated with humans and sheep. Reasons for the observed patterns of resistance must be explored to reduce the burdens of MRSA resistance. Furthermore, the present study did not confirm the MRSA resistance genes such as mecA and spa typing to ascertain the polymorphism in the X-region using appropriate molecular techniques. Hence more studies need to be conducted to elucidate these findings using robust techniques.

Colonization of methicillin-resistant Staphylococcus aureus among healthcare students: an integrative review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a worldwide concern given its presence even in non-hospitalized healthy individuals, such as university students.

OBJECTIVE

To identify in the literature the prevalence of colonization by MRSA among healthcare students.

DESIGN AND SETTING

Integrative review of the literature conducted in Universidade Federal do Piauí.

METHOD

A search for primary studies was performed in the following databases: Medical Literature Analysis and Retrieval System on-line; Cumulative Index to Nursing and Allied Health Literature; Web of Science; Scopus; and LILACS.

RESULTS

This review included 27 studies that demonstrated MRSA infection prevalence ranging from 0.0 to 15.3% among students.

CONCLUSION

The prevalence of colonization of MRSA among healthcare students is high, and the nasal cavity was cited as an important reservoir location for these microorganisms.

Staphylococcal trafficking and infection - from 'nose to gut' and back

Staphylococcus aureus is an opportunistic human pathogen, which is a leading cause of infections worldwide. The challenge in treating S. aureus infection is linked to the development of multidrug-resistant strains and the mechanisms employed by this pathogen to evade the human immune defenses. In addition, S. aureus can hide asymptomatically in particular ‘protective’ niches of the human body for prolonged periods of time. In the present review, we highlight recently gained insights in the role of the human gut as an endogenous S. aureus reservoir next to the nasopharynx and oral cavity. In addition, we address the contribution of these ecological niches to staphylococcal transmission, including the roles of particular triggers as modulators of the bacterial dissemination. In this context, we present recent advances concerning the interactions between S. aureus and immune cells to understand their possible roles as vehicles of dissemination from the gut to other body sites. Lastly, we discuss the factors that contribute to the switch from colonization to infection. Altogether, we conclude that an important key to uncovering the pathogenesis of S. aureus infection lies hidden in the endogenous staphylococcal reservoirs, the trafficking of this bacterium through the human body and the subsequent immune responses.

Methicillin-resistant Staphylococcus aureus in Nepal

Staphylococcus aureus is both a frequent commensal and a leading cause of endocarditis, bacteremia, osteomyelitis and skin and soft tissue infections and device-related infections. We performed this minireview to summarize the prevalence of Staphylococcus aureus among clinical samples and estimate the proportion of methicillin-resistant Staphylococcus aureus. The prevalence of Staphylococcus aureus among clinical isolates in Nepal is 34.5%. On average, the proportion of multi-drug resistance in Staphylococcus aureus is 57.1%. Methicillin-resistant Staphylococcus aureus accounts for a total of 41.7%. Inducible clindamycin resistance was detected in about 35% of the isolates. A regular antimicrobial resistance surveillance mechanism is necessary to mitigate the development of resistance among organisms and further spread of superbugs like methicillin-resistance Staphylococcus aureus.

Prevalence of Staphylococcus aureus Nasal Carriage and Methicillin-resistant S. aureus Among Medical Students: A Systematic Review and Meta-analysis

Context: Evaluating the prevalence of Staphylococcus aureus nasal carriage and methicillin-resistant S. aureus (MRSA) that are sources of nosocomial infection among medical students. Evidence Acquisition: Electronic databases were searched by preferred subject headings and free-text keywords. After omitting duplicates, retrieved articles were screened by two independent reviewers in a three-step process based on inclusion criteria. Then, reviewers critically appraised the selected studies by JBI checklists and extracted the required data. Finally, the pooled prevalence rates of S. aureus nasal carriage and MRSA were meta-analyzed by Stata V.16 software. The heterogeneity of included studies was calculated by I2 and chi-square. Subgroup analysis was carried out according to study designs, as well as the continent origin of clinical and preclinical students. Results: Of 858 retrieved studies, 15 were included in the meta-analysis. The results showed that the pooled prevalence of nasal S. aureus carriage was 28% [prevalence rate: 0.028, 95% CI: 0.21 - 0.34, P < 0.001, I2: 96.40%, chi2: 360.98 (df = 14)]. The prevalence of S. aureus among clinical students was 33% (pooled prevalence rate: 0.33, 95% CI: 0.18 - 0.47) whereas, in preclinical students, it was 25% (pooled prevalence rate: 0.25, 95% CI: 0.23 - 0.28). Also, in a subgroup analysis of continents, Australia (Oceania) had the highest prevalence rate. According to an evaluation of publication bias, the distribution of studies was very high. Moreover, pooled MRSA prevalence among medical students was 2% (prevalence rate: 0.02 95% CI: 0.01 - 0.03, P < 0.001). Conclusions: In this meta-analysis, S. aureus and MRSA prevalence rates among medical students were estimated at 28% and 2%, respectively. More attention should be given to the prevention of MRSA colonization and screening strategies among medical students across the world.

Prevalence of Methicillin Resistant Staphylococcus aureus Nasal Colonizers among Basic Science MBBS and BDS Students of Kathmandu Medical College

Introduction:

Methicillin-Resistant Staphylococcus aureus exhibit multiple drug resistance phenotypes. Colonizers harboring Methicillin-Resistant Staphylococcus aureus are often associated with its outbreaks in both hospital and community settings. This study was done to determine the prevalence of nasal carriage rate of Methicillin-Resistant Staphylococcus aureus among basic science MBBS and BDS students of Kathmandu Medical College.

Methods:

A descriptive cross-sectional study was done in Kathmandu Medical College from March 5 to June 5 2020. Ethical clearance was obtained from the Institutional Review Committee with reference no. 040320201. A convenient sampling method was used, and the sample size was calculated with a prevalence of 50%. Two hundred students studying MBBS and BDS were enrolled.

The nasal swab was collected and processed using standard microbiological methods. The data obtained were computed and analyzed using Statistical Package for Social Sciences 16.0 Version.

Results:

Among 200 participants, 9 (4.5%) were found to be nasal carriers of Methicillin-Resistant Staphylococcus aureus.

Conclusions:

Colonization of anterior nares by Methicillin-Resistant Staphylococcus aureus in apparently healthy individuals is a cause of concern. Education regarding Methicillin-Resistant Staphylococcus aureus, its carrier and significance, and its screening must be included early on in MBBS and BDS.

Prevalence, risk-factors, and antimicrobial susceptibility profile of methicillin-resistant Staphylococcus aureus (MRSA) obtained from nares of patients and staff of Sokoto state-owned hospitals in Nigeria

Aim: The aim of the study was to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) obtained from the nasal cavity of participants and investigate the antibiotic resistance profiles of the isolates from Sokoto state, Nigeria.

Methods: Nasal swabs of both nares were obtained from 378 participants across three study centers within the six-month study period. The Staphylococcus aureus isolates recovered were characterized, and their resistance phenotype determined in conjunction with MRSA prevalence.

Results: Phenotypic screening of isolates obtained in this study revealed a total of 131 (17.3%) coagulase-positive Staphylococci out of 756 samples. Of this number, there were 81 (61.8%) S. aureus, 36 (27.5%) Staphylococcus intermedius, 6 (4.5%) Staphylococcus hyicus, and 8 (6.1%) Staphylococcus schleiferi.

Conclusion: This study found a prevalence of 61.8% and 46.9% of S. aureus and MRSA among the studied hospitals in Sokoto state, thus demonstrating that the nares of the hospital populace are not free from S. aureus and MRSA colonization.

Genetic Diversity and Virulence Factors of S. aureus Isolated from Food, Humans, and Animals

Staphylococcus aureus is a commensal bacterium in humans and animals able to adapt to multiple environments. The aim of this study was to compare the genetic diversity and virulence profiles of strains of S. aureus isolated from food (29 strains), humans (43 strains), and animals (8 strains). 80 lipase-producing strains belonging to a biobank of 360 isolates, identified phenotypically as S. aureus, were selected. Confirmation of the species was made by amplifying the spA gene and 80% (64/80) of the strains were confirmed within this species. The virulence profile of each of the isolates was determined by PCR. The seA gene coding for enterotoxin A was found in 53.1% of the strains, the saK gene, which codes for Staphylokinase, was amplified in 57.8% of the strains, and, finally, the hlB gene coding for β-Hemolysin was amplified in 17.2%. The profile of antimicrobial resistance was determined by the Kirby Bauer method showing that the strains from food presented greater resistance to erythromycin (40.7%) and ciprofloxacin (18.5%) while in strains isolated from humans were to erythromycin (48.4%) and clindamycin (21.2%). Also, in strains from animals, a high resistance to erythromycin was observed (75%). The frequency of MRSA was 12.5% due to the presence of the mec gene and resistance to cefoxitin. Of the total strains, 68.7% were typed by PCR-RFLP of the coa gene using the AluI enzyme; derived from this restriction, 17 profiles were generated. Profile 4 (490 bp, 300 bp) was the most frequent, containing a higher number of strains with a higher number of virulence factors and antimicrobial resistance, which is associated with greater adaptation to different environments. In this study, a wide genetic diversity of strains of S. aureus from different foods, humans, and animals was found. This demonstrates evolution, genetic versatility, and, therefore, the adaptation of this microorganism in different environments.

Antibiotic susceptibility profile and prevalence of mecA and lukS-PV/lukF-PV genes in Staphylococcus aureus isolated from nasal and pharyngeal sources of medical students in Ecuador

BACKGROUND

Staphylococcus aureus is a common nasal colonizer in 20-30% of the general population. When mucosal and cutaneous barriers are disrupted, S. aureus can cause severe infections. While MRSA nasal carriers have an increased risk of infections when compared to non-carriers, prolonged exposure to the hospital environment may cause an increase in carriage of MRSA.

MATERIALS AND METHODS

A survey questionnaire was filled for analyzing risk factors of colonization. Swab isolates were identified as S. aureus by traditional microbiological assays. Antibiotic susceptibility profiles were performed following the CLSI standard guidelines. Multiplex PCR was conducted to determine the presence of genes mecA and lukS-PV/lukF-PV. Chi-squared, univariate, and multivariate logistic regressions were applied to find statistically significant associations between risk factors and the presence of S. aureus and MRSA.

RESULTS

One hundred and eighty-six isolates were identified as S. aureus. The strains showed high resistance to penicillin, oxacillin, azithromycin, erythromycin, clindamycin (inducible), and tetracycline. The overall prevalence of MRSA in medical students was 45.9% [40.4-51.6] 95% CI. PCR showed a prevalence of mecA gene in MRSA isolates of 6.1% while lukS-PV/lukF-PV gene was present in 3.2% [1.2-6.9] 95% CI of the S. aureus samples. The risk factors frequency of antibiotic intake and repeated visits to hospitals demonstrated statistical significance.

CONCLUSION

S. aureus and MRSA isolates have a high prevalence of colonization, and antibiotic resistance in the population studied. MRSA resistance was not related to the presence of the mecA gene. The prevalence of PVL genes was low, but it could represent a risk because they are circulating in the community.

Methicillin-resistant Staphylococcus aureus carriage among medical students of Jimma University, Southwest Ethiopia

Objectives

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are often difficult to manage due to its resistance to multiple antibiotics. This study aimed to determine the nasal carriage of MRSA and its antimicrobial susceptibility patterns among medical students at the Jimma University medical center (JUMC), Southwest Ethiopia.

Methods

An institution based cross-sectional study was conducted at the JUMC from May to August; 2016. A total of 371 participants were systematically selected. Demographic data was collected using pre-designed questionnaire. Nasal swabs were collected following standard microbiological methods. MRSA was detected using cefoxitin (30μg) disc (Oxoid, UK); and antimicrobial susceptibility tests were performed by disc diffusion method.

Results

A total of 371 students were included. Of these, 84.9% (315/371) were males. The overall prevalence of nasal carriage of S. aureus and MRSA among medical students at JUMC were 22.1% (82/371) and 8.4 % (31/371), respectively. The carriage rate of MRSA among medical intern (20% (16/80)) was higher compared with clinical year-I (3.6% (6/166)) and year-II (7.2% (9/125)) students. Resistance against trimethoprim-sulfamethoxazole, tetracycline and ciprofloxacin were 83.9%, 64.5% and 51.6%, respectively. Longer stay in hospital was significantly associated with the acquisition of MRSA (X² = 6.93, P value = 0.031).

Conclusion

The prevalence of nasal carriage of MRSA was high. Longer stay in hospital environment was associated with the acquisition of MRSA. These findings suggest that infection control efforts focusing the performance of antimicrobial stewardship could have a significant impact on MRSA incidence in this setting.

Nasal Carriage Rate, Antimicrobial Susceptibility Pattern, and Associated Factors of Staphylococcus aureus with Special Emphasis on MRSA among Urban and Rural Elementary School Children in Gondar, Northwest Ethiopia: A Comparative Cross-Sectional Study

INTRODUCTION

Staphylococcus aureus is a Gram-positive, catalase-positive, and coagulase-positive bacterial species commonly found on the skin and in the nose of most healthy individuals. The anterior nares of nose are the most frequent carriage sites for S. aureus in both adults and children. Methicillin resistance among S. aureus isolates has steadily increased worldwide.

OBJECTIVE

The main objective of this study was to determine nasal carriage rate, antimicrobial susceptibility pattern, and associated risk factors of Staphylococcus aureus with special emphasis on MRSA among urban and rural elementary school children in Gondar, Northwest Ethiopia.

METHOD

A community based comparative cross-sectional study was conducted on 622 urban and rural elementary school children in Gondar from January 1st to March 30th, 2018. Data was collected using a questionnaire and nasal swab samples were collected by sterile cotton tip swab moistened with sterile normal saline. Collected samples were inoculated on mannitol salt agar and incubated aerobically at 37°C for 24 hrs. S. aureus was confirmed by observing colony characteristics and biochemical tests. MRSA was detected using cefoxitin disc by Modified Kirby-Bauer disk diffusion technique. Finally data was entered, cleared, and checked using Epi-info version 7 and exported to SPSS version 20 for analysis. Odds ratio and logistic regression were used for statistical association. P-value ≤ 0.05 at 95% CI was considered for statistical association.

RESULT

Of the 622 school children, the overall prevalence of S. aureus was 143/622 (23%). Of them, 14/143 (9.79%) were MRSA. The carriage rate in urban schools was 83/622 (13.3%) whereas it was 60/622 (9.6%) in rural schools. The prevalence of MRSA among urban schools, 9.1%, was higher than their urban counterparts, 0.7%. Gentamycin, clindamycin, and ciprofloxacin were the most effective whereas penicillin and tetracycline were resistant. Children's fathers' educational status and number of children in class room were significantly associated with S. aureus but only living in urban of children significantly associated with MRSA.

CONCLUSION

This study showed high prevalence of S. aureus and MRSA, 143/622 (23%) and 14/143 (9.79%), respectively. So, decolonization of nasal carriers of MRSA and reducing the number of students per classroom should be addressed. Moreover, regular large scale survey should be conducted to assess the burden and intervene accordingly.

School environmental contamination of methicillin-sensitive Staphylococcus aureus as an independent risk factor for nasal colonization in schoolchildren: An observational, cross-sectional study

Objective

We aim to assess the similarities of proportional, phenotypic, and molecular characteristics between the school environment and schoolchildren on methicillin-sensitive S. aureus (MSSA) isolates.

Methods

A cross-sectional study was conducted between March 2016 and August 2016 in eight elementary schools in Guangzhou, China. Nasal swabs from students and environmental swabs from school environments were collected. Univariate and multivariate logistic regression analyses under a multistage stratified cluster cross-sectional survey design were performed to access the prevalence relationship and influencing factors, respectively. Phenotypic and molecular characterizations of MSSA isolates were conducted using the Kirby-Bauer disk diffusion method and polymerase chain reaction assays, respectively.

Results

In total, 1705 schoolchildren and 1240 environmental samples from 40 classes in eight elementary schools obtained between March and August 2016 were include in this study. The rates of MSSA prevalence among schoolchildren and the environment were 11.44% (195/1705) and 4.60% (57/1240), respectively. The odds ratios and 95% confidence intervals (CIs) on the prevalence of MSSA isolates were 1.11 (95% CI, 1.05–1.29; P = 0.010) and 1.04 (95% CI, 1.01–1.07; P = 0.003) for the school or class environment and students, respectively. Similar phenotypic and molecular characteristics were identified between schoolchildren and the environment. A cause and effect relationship could not be established because the study design was cross-sectional.

Conclusions

Because of the cross-sectional design, we can reveal the association between school environment and schoolchildren on MSSA, but it is not a cause and effect relationship.

Nasal and Pharyngeal Colonization by Bacterial Pathogens: A Comparative Study between Preclinical and Clinical Sciences Medical Students

Background

Upper respiratory tract is one of the commonest sites for microbial colonization. The colonized individuals are at risk of infections and can be a source of transmission of pathogens. Medical students are frequently exposed to a variety of infectious agents and more likely to get colonized by them. This study was aimed to determine the prevalence and to compare the colonization rates of nasal and pharyngeal bacterial pathogens among preclinical and clinical sciences medical students.

Methods

This cross-sectional study was conducted among 100 preclinical and 100 clinical sciences medical students. Isolation, identification, and antibiotic susceptibility testing of the isolates were performed by standard microbiological techniques.

Results

The nasal colonization by S. aureus and MRSA was 35% (70/200) and 19.5% (39/200), respectively. The nasal colonization by S. aureus and MRSA was significantly higher among clinical sciences students as compared to preclinical sciences students. Pharyngeal colonization by Haemophilus influenzae was significantly higher among clinical sciences students as compared to preclinical sciences students. The pharyngeal colonization by beta-hemolytic streptococci (nongroup A) was higher among preclinical sciences students than clinical sciences students.

Conclusion

The nasal colonization by S. aureus and MRSA was higher among clinical sciences students. Pharyngeal colonization by potential bacterial pathogens was higher among clinical sciences students than preclinical students. Periodic screening of MRSA and potential throat pathogens of clinical sciences students and may reduce the incidences of nosocomial transmission of pathogens.

Dose-response associations of methicillin-resistant Staphylococcus aureus between school environmental contamination and nasal carriage by elementary students

Background

Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious infections in elementary students. Therefore, we aimed to elucidate the quantitative associations of school environmental contamination with nasal carriage of MRSA by students in a dose-response manner. Phenotypic and molecular characterizations were performed to further assess the associations.

Materials and methods

A cross-sectional study was conducted from March to August 2016 in eight elementary schools in Guangzhou, China. A multistage stratified cluster sampling design was used to include Chinese students and selected classes. Nasal swabs from students and environmental swabs from the schools were collected. The dose-response relationship was examined using multivariate logistic regression modeling with cluster-correlated robust variance estimates to account for correlations of isolates between the environment and the students.

Results

The prevalence rates of MRSA among 1705 students and 1240 environment samples were 10.15% and 3.87%, respectively. There were positive prevalence associations of school (odds ratio 1.09, 95% confidence interval [CI] 1.05–1.13) and class (odds ratio 1.03, 95% CI 1.01–1.06) environmental contamination with nasal carriage of MRSA isolates by students.

Conclusions

Comparisons of MRSA isolates between the environment and the students in terms of phenotypic and molecular characterization were mostly insignificant. School environmental contamination with MRSA was positively associated with MRSA nasal carriage by elementary students. Disinfection measures and education regarding hand hygiene should be considered to decrease the prevalence of MRSA nasal carriage among students.

The effect of fennel essential oil in combination with antibiotics on Staphylococcus aureus strains isolated from carriers

An increase in the number of staphylococcal infections and carriers among medical staff has forced us to seek more and more effective antibacterial agents. Bacteria from the Staphylococcus genus possessing different mechanisms of resistance are the cause of nosocomial infections. The objective of our investigations was susceptibility of S. aureus strains isolated from nasal vestibule of medical students to fennel essential oil. The GC-MS analysis of fennel essential oil revealed eleven constituents among which a majority of trans-anethole (80%) was found. The D-tests showed iMLS_B (80%), cMLS_B and MS_B (10%) resistant phenotypes of S. aureus. The S. aureus isolates were intermediate to mupirocin (45%). Fennel essential oil increased the inhibition zone around cefoxitin, mupirocin, co-trimoxazole and ciprofloxacin with statistical significance. Our research showed that the fennel essential oil in combination with mupirocin may be considered as a natural alternative in eradication of S. aureus with iMLS_B, cMLS_B, MS_B resistant phenotypes and is able to decrease the growth rate of antibiotic resistance.

Hospital clones of methicillin-resistant Staphylococcus aureus are carried by medical students even before healthcare exposure

Background

Methicillin-resistant Staphylococcus aureus (MRSA) strains are prevalent in healthcare and the community. Few studies have examined MRSA carriage among medical students.

The aim of this study is to examine Staphylococcus aureus (SA) carriage, and particular MRSA, over time in cohort medical students

Methods

Prospective collection of nasal swabs from medical students in Israel and assessment of SA carriage. Three samples were taken per student in preclinical and clinical parts of studies. Antibiotic susceptibilities were recorded and MRSA typing was performed by staphylococcal cassette chromosome mec (SCCmec) types, Panton Valentine Leukocidin (PVL) encoding genes, and spa types. Clonality was assessed by pulsed-field gel electrophoresis.

Results

Among 58 students, SA carriage rates increased from 33% to 38% to 41% at baseline (preclinical studies), 13 and 19 months (clinical studies), respectively (p = 0.07). Methicillin-susceptible SA (MSSA) carriage increased in the clinical studies period (22 to 41%, p = 0.01). Overall, seven students (12%) carried 13 MRSA isolates. MRSA isolates were PVL negative and were characterized as SCCmecII-t002, SCCmecIV-t032, or t12435 with untypable SCCmec. MRSA carriage during the pre-clinical studies was evident in 4/7 students. Two students carried different MRSA clones at various times and persistent MRSA carriage was noted in one student. Simultaneous carriage of MRSA and MSSA was not detected.

Conclusions

MSSA carriage increased during the clinical part of studies in Israeli medical students. Compared with previous reports, higher rates of MRSA carriage were evident. MRSA strains were genotypically similar to Israeli healthcare-associated clones; however, carriage occurred largely before healthcare exposure, implying community-acquisition of hospital strains.