Prevalence, antimicrobial susceptibility pattern and multidrug resistance of methicillin-resistant Staphylococcus aureus isolated from clinical samples at a tertiary care teaching hospital: an observational, cross-sectional study from the Himalayan country, Nepal

Prevalence and Outcome of Infections Caused by Staphylococcus aureus Strains Harboring the Panton-Valentine Leukocidin Gene

BACKGROUND

Staphylococcus aureus, especially Methicillin-resistant S. aureus (MRSA), is responsible for various hospital-acquired (HA) and community-acquired (CA) infections. Mec A gene responsible for methicillin resistance is encoded in Staphylococcal cassette chromosome gene (SCC). CA-MRSA strains often carry SCC mec IV / SCC mec V and Panton-Valentine leukocidin (PVL) genes. PVL-producing MRSA can cause severe skin or soft tissue infections.

AIM

This study estimates the prevalence and outcome of infections caused by PVL-producing S. aureus strains in outdoor and indoor patients of a tertiary care hospital in Western Maharashtra, India.

METHOD

This cross-sectional study included 274 S. aureus strains isolated from various clinical samples during the study period. Detection of Methicillin resistance was done by the cefoxitin disk method and by automated antimicrobial susceptibility (Vitek 2) method. Multiplex PCR was done for the detection of MecA, SCC type IV, Nuc, and PVL gene using appropriate primers.

RESULTS

Out of 274 S. aureus strains, 151 (55%) were methicillin resistant. The PVL gene was detected in 187 (70.8%) strains and SCC IV in 116 (43.9%) strains. Mec A was detected in all MRSA strains. Both PVL-producing MRSA (83.4%) and MSSA (78.78) strains were isolated commonly from pus samples. Patients with PVL-producing S. aureus infections required more surgical interventions (18.1%) as compared to those with PVL-negative infections (5.19%) (p-value = 0.006). The PVL gene was associated with SCC IV in 84 (58.7%) strains, while 35 (24.4%) PVL-positive strains were not associated with SCC IV. Few SCC IV and PVL-positive S. aureus strains (17 strains) have produced HA infections.

CONCLUSION

The prevalence of the PVL gene is 70.8% in S. aureus. PVL and SCC IV genes are markers of CA infection. MRSA strains harbouring PVL and SCC IV gene producing HA infections is a cause of concern. This suggests infiltration of SCC IV gene producing S. aureus strains in hospital settings. Proper antibiotic stewardship practices, strict aseptic techniques, identification, and treatment of carriers are needed to control the spread of CA-MRSA in hospitals and in the community.

Insights into biofilm-mediated mechanisms driving last-resort antibiotic resistance in clinical ESKAPE pathogens

The rise of antibiotic-resistant bacteria poses a grave threat to global health, with the ESKAPE pathogens, which comprise Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. being among the most notorious. The World Health Organization has reserved a group of last-resort antibiotics for treating multidrug-resistant bacterial infections, including those caused by ESKAPE pathogens. This situation calls for a comprehensive understanding of the resistance mechanisms as it threatens public health and hinder progress toward the Sustainable Development Goal (SDG) 3: Good Health and Well-being. The present article reviews resistance mechanisms, focusing on emerging resistance mutations in multidrug-resistant ESKAPE pathogens, particularly against last-resort antibiotics, and describes the role of biofilm formation in multidrug-resistant ESKAPE pathogens. It discusses the latest therapeutic advances, including the use of antimicrobial peptides and CRISPR-Cas systems, and the modulation of quorum sensing and iron homeostasis, which offer promising strategies for countering resistance. The integration of CRISPR-based tools and biofilm-targeted approaches provides a potential framework for managing ESKAPE infections. By highlighting the spread of current resistance mutations and biofilm-targeted approaches, the review aims to contribute significantly to advancing our understanding and strategies in combatting this pressing global health challenge.

Global prevalence of macrolide-resistant Staphylococcus spp.: a comprehensive systematic review and meta-analysis

Background

Staphylococcus is a genus of bacteria responsible for various infections ranging from mild skin to severe systemic diseases. Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) are significant challenges owing to their resistance to multiple antibiotics, including macrolides, such as erythromycin, clarithromycin, and azithromycin.

Objective

This study aimed to systematically review and synthesize data on the prevalence of macrolide resistance in Staphylococcus spp., identify trends and changes in resistance patterns over time, and assess how testing methods and guidelines affect reported resistance rates.

Methods

The study conducted a systematic search of the Scopus, PubMed, Web of Science, and EMBASE databases. Studies have reported the proportion of macrolide-resistant Staphylococcus spp. Two authors independently extracted and analyzed the data using a random-effects model. Heterogeneity was assessed, and subgroup analyses were performed based on country, continent, species, AST guidelines, methods, and period.

Results

In total, 223 studies from 76 countries were included. The pooled prevalence of resistance to erythromycin, clarithromycin, and azithromycin were 57.3, 52.6, and 57.9%, respectively. Significant heterogeneity was observed across studies (I2 > 95%, p < 0.001). Oceania (72%) had the highest erythromycin resistance, whereas Europe had the lowest (40.7%). Subgroup analyses revealed variations in resistance based on the species, with higher resistance in MRSA than in MSSA and CoNS than in other species. Over time, a slight decrease in erythromycin resistance has been observed (59.6% from 2015-2019 to 55% from 2020-2023).

Conclusion

This study emphasizes the high prevalence of macrolide resistance in Staphylococcus spp. and its notable regional variation. These findings highlight the necessity for standardized methodologies and global surveillance to manage macrolide resistance effectively. Controlling antibiotic resistance should prioritize enhancing public health measures and updating treatment guidelines.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=557756, CRD42024557756.

mecA and PVL genes in methicillin-resistant Staphylococcus aureus from clinical specimens: a cross-sectional hospital based study from Nepal

Background and Objectives

Staphylococcus aureus has increasingly been associated with community and healthcare-associated infections worldwide and contributes to treatment failures due to the emergence of multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) strains. We aimed to determine the prevalence and antibiotic susceptibility pattern of MRSA isolated from patients attending a burn center and to detect mecA and PVL genes among MRSA isolates.

Materials and Methods

A cross-sectional hospital based study was conducted on 1950 clinical samples collected from hospital inpatients and outpatients of Kirtipur Hospital, which is a burn specialist hospital in Kathmandu, Nepal. Each sample underwent conventional cultural methods for bacterial isolates identification.

Results

Out of 1950 samples, 452 (23.2%) samples showed bacterial growth, of which 109 isolates (24.1%) were identified as Gram positive and 343 (75.9%) as Gram negative bacteria. Among the Gram positive bacteria, 53 (48.62%) were Staphylococcus aureus. Of the total S. aureus isolates, 40 (75.5%) were MRSA and 48 (90.6%) were MDR. Of the 40 MRSA isolates, 29 (72.5%) carried the mecA gene and 3 (7.5%) harbored PVL gene.

Conclusion

The high prevalence of MRSA in a burn unit underscores the need for more rigorous infection control practices that follow standard protocols to reduce MRSA transmission in both individuals and the hospital environment.

Seasonal Trends and Antibiotic Resistance Profiles of Bacterial Pathogens in Indian Clinical Isolates

Introduction Bacterial diseases exhibit seasonal trends, necessitating their monitoring for outbreak prediction, treatment optimization, and infection control. This study explores seasonal trends, temperature correlations, and antimicrobial resistance profiles of key pathogens in an Indian tertiary care setting. Methodology This cross-sectional study analyzed bacterial isolates from 1,562 patient samples, including Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, and Enterococcus faecalis. Monthly infection rates and seasonal patterns were visualized using heatmaps and time-series graphs. Pearson's correlation assessed the relationship between these infection rates and temperature. Antibiotic susceptibility was evaluated using VITEK2, with resistance patterns visualized in R. Results Infections peaked in April (n = 163, 10.43%) and March (n = 161, 10.30%), with S . aureus as the most common pathogen (n = 271, 25.64%), followed by K . pneumoniae (n = 201, 19.02%) and P . aeruginosa (n = 178, 16.84%). Seasonal trends showed S. aureus infections peaked in summer (n = 45, 16.6%), while P. aeruginosa (n = 27, 15.2%) and E. faecalis (n = 24, 25.5%) peaked in winter. Temperature correlated positively with S. aureus infection (r = 0.814, P = 0.001) and negatively with P. aeruginosa (r = -0.845, P = 0.001), and E . faecalis (r = -0.618, P = 0.032), with no correlation observed for K. pneumoniae, A. baumannii, and E. coli. Multi-drug resistance (MDR), extensively drug resistance (XDR), and pandrug resistance were more prevalent in Gram-negative than in Gram-positive bacteria.  Conclusions This study reveals temperature-driven seasonal patterns in bacterial infections, aiding outbreak prediction and prevention. The findings emphasize the threat of multidrug resistance, particularly in Gram-negative bacteria, reinforcing the need for enhanced infection control and targeted antibiotic stewardship.

A Decade-Long Analysis of Trends in Antimicrobial Resistance in a Neurosurgical Hospital in Kathmandu, Nepal

Multidrug-resistant (MDR) bacteria cause infections with higher risks of morbidity, mortality, and financial burden. Understanding the antimicrobial resistance patterns of these pathogens is crucial for effective treatment and managing resistance. Therefore, this retrospective study examined the prevalence, causes, and trends in antimicrobial resistance in bacterial infections at a neurosurgical hospital in Nepal. We analyzed the demographics, bacteriological profiles, and antimicrobial susceptibility results in patients who visited Dirghayu Guru Hospital and Research Center, Kathmandu, Nepal, between January 2014 and January 2024, using SPSS, version 17.00. Among 4758 patients, 465 (9.77%) had infections caused by 571 bacteria. Of them, 435 (93.55%) patients had urinary tract infections, 89 (19.14%) had bloodstream infections, and 31 (6.67%) had respiratory tract infections. Klebsiella pneumoniae (n = 172, 30.12%) was the predominant bacteria. Proportions of drug-resistant Enterobacterales and gram-positive cocci among drug-resistant bacteria against tetracyclines were 83.33% and 45.83%, cephalosporins were 78.02% and 40.45%, quinolones were 72.25% and 50.00%, aminoglycosides were 65.14% and 43.53%, carbapenems were 62.96% and 30.00%, penicillins were 54.55% and 57.89%, and penicillin with beta-lactamase inhibitors (PwBLIs) were 40.54% and 42.31%, respectively. Proportions of drug-resistant nonfermenters among drug-resistant bacteria showed 100.00% resistance to these antimicrobials. MDR isolates (n = 118, 20.67%) were 100.00% susceptible to piperacillin-tazobactam and 83.33% to polymyxin B. Over the years, resistance increased for cephalosporins (48.15%-60.53%) but decreased for carbapenems (50.00%-33.33%), penicillins (64.29%-42.31%), PwBLIs (50.00%-12.50%), aminoglycosides (60.00%-49.12%), tetracyclines (100.00%-16.67%), and polymyxins (76.22%-16.67%). One-tenth of hospital-visiting patients had bacterial infections, with three-fourths involving Enterobacterales and one-fifth involving MDR bacteria. In recent years, resistance to cephalosporins has increased, whereas resistance to other beta-lactams, aminoglycosides, and polymyxins has decreased.

Myrtenol's Effectiveness against Hospital-Acquired Methicillin-Resistant Staphylococcus aureus: Targeting Antibiofilm and Antivirulence Properties

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) several years ago highlighted the challenge of multidrug-resistant infections, emphasizing the critical need for innovative treatment approaches. Myrtenol, known for its antibacterial and antibiofilm properties, holds promise as a potential treatment option. This study aimed to evaluate the effectiveness of myrtenol against MRSA. The collected MRSA isolates were assessed for antimicrobial susceptibility following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2023. Biofilm formation by MRSA was evaluated using the tissue culture plate (TCP) technique. The minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal biofilm inhibitory concentration (MBIC) of myrtenol against MRSA were determined both individually and in combination with antibiotics. Real-time PCR was employed to investigate the impact of myrtenol on the expression of virulence genes (sarA, agrA, and icaD) across the isolates. In this study, MRSA was identified in 90 out of 400 cases (22.5%) of hospital-acquired pathogens. Among the collected MRSA isolates, 53 out of 90 (59%) were found to produce biofilms. The MIC of myrtenol was comparable to the MBC across all tested isolates, they were almost the same. Combinations of myrtenol with most tested antibiotics exhibited synergistic effects exceeding 60%. Among the 53 biofilm-producing isolates, 45 isolates (85%) expressed the sarA gene, 49% expressed the agrA gene, and all biofilm-producing MRSA isolates (100%) expressed the icaD gene. A notable reduction in the relative quantity (RQ) values of virulence gene expression was observed after treatment with the MBIC of myrtenol across all tested isolates. Myrtenol demonstrated strong antimicrobial activity against MRSA, notably reducing the expression of key virulence genes linked to biofilm formation. This suggests its potential as a therapeutic agent for treating biofilm-associated MRSA infections.

Prevalence and Antimicrobial Susceptibility Pattern of MRSA amongst Patients from an Indian Tertiary Care Hospital: An Eye Opener

Staphylococcus aureus (S. aureus) is a very common human pathogenic microorganism that can cause a variety of infectious diseases, including skin and soft tissue infections, endocarditis, osteomyelitis, bacteremia, and lethal pneumonia. About one-third of the common population is colonized with S. aureus. MRSA is a formidable pathogen known to cause high mortality & morbidity, that poses a significant threat to public health worldwide. Presence of MRSA strains, resistant to multiple antibiotics especially in hospital stay, has complicated the management of infections caused by this bacterium. The aim of this study was to shed light on the prevalence and antimicrobial sensitivity pattern of MRSA among patients in a tertiary care center located in Faridabad, Haryana. This cross-sectional observational study was conducted in the Department of Microbiology, ESIC Medical College & Hospital, a 510 bedded tertiary care teaching hospital in Faridabad, Haryana, India. All wound samples including pus, exudates, wound swab and tissue samples received for aerobic culture and antimicrobial sensitivity from various clinical departments from January 2019 to July 2019 were included in this study. A total of 747 samples were received from January 2019-July 2019. Mean age of this study population was found to be 50.7 ± 14.8 years. Out of 747 samples, 226 (30.25%) were culture positive. Among the S. aureus isolates, methicillin resistance was seen amongst 39 (58.2%). Antibiotic Susceptibility results of S. aureus showed 100% resistance to Penicillin along with 100% resistance to Fluoroquinolones in both MRSA and MSSA. High prevalence of MRSA amongst patients highlights the importance of continued surveillance and implementation of antimicrobial stewardship program to control the menace of antimicrobial resistance. Strict adherence to Infection Control practices its regular follow up to assess the effectiveness of any hospital infection control measures taken is the key.

A retrospective study of the predictors of mortality among patients in intensive care units at North West-Bank hospitals in Palestine

OBJECTIVES

The intensive care unit (ICU) mortality rate remains high, especially in developing countries, regardless of the advances in critical management. There is a lack of studies about mortality causes in hospitals and particularly ICUs in Palestine.This study evaluated the demographic and clinical characteristics of critically ill patients and determined the predictors of mortality among patients in the ICU.

METHODS

A retrospective study assessed all patients who stayed in the ICU for more than 24 h from January 2017 to January 2019. Data were collected from the patient's files. Patient characteristics (background, clinical variables, and comorbidities) were recorded.

RESULTS

The study included 227 eligible ICU patients. The cases' mean age was 55.5 (SD ± 18.2) years. The overall ICU mortality rate was 31.7%. The following factors were associated with high adjusted mortality odds: admission from inside the hospital (adjusted odds ratio (aOR), 2.1, 95% CI: 1.1-3.9, p < 0.05), creatinine level ≥2 mg/dl on admission (aOR, 2.7, 95% CI: 1.3-5.8, p < 0.01), hematology malignancy patients (aOR, 3.4, 95% CI: 1.6-6.7, p = 0.001), immune-compromised (aOR, 2.5, 95% CI: 1.3-4.7, p < 0.01), septic shock (aOR, 27.1, 95% CI: 7.9-88.3, p < 0.001), hospital-acquired infections (aOR: 13.4, 95% CI: 4.1-57.1, p < 0.001), and patients with multiple-source infection (aOR: 16.3, 95% CI: 6.4-57.1, p < 0.001). Also, high SOFA and APACHE scores predicted morality (p < 0.001).

CONCLUSION

The mortality rate among ICU patients was high. It was higher among those admitted from the hospital wards, septic shock, hospital-acquired infection, multiple infection sources, and multi-drug resistance infections. Thus, strategies should be developed to enhance the ICU environment and provide sufficient resources to minimize the effects of these predictors.

Aerosol-Mediated Spread of Antibiotic Resistance Genes: Biomonitoring Indoor and Outdoor Environments

Antimicrobial resistance (AMR) has emerged as a conspicuous global public health threat. The World Health Organization (WHO) has launched the "One-Health" approach, which encourages the assessment of antibiotic resistance genes (ARGs) within an environment to constrain and alleviate the development of AMR. The prolonged use and overuse of antibiotics in treating human and veterinary illnesses, and the inability of wastewater treatment plants to remove them have resulted in elevated concentrations of these metabolites in the surroundings. Microbes residing within these settings acquire resistance under selective pressure and circulate between the air-land interface. Initial evidence on the indoor environments of wastewater treatment plants, hospitals, and livestock-rearing facilities as channels of AMR has been documented. Long- and short-range transport in a downwind direction disseminate aerosols within urban communities. Inhalation of such aerosols poses a considerable occupational and public health risk. The horizontal gene transfer (HGT) is another plausible route of AMR spread. The characterization of ARGs in the atmosphere therefore calls for cutting-edge research. In the present review, we provide a succinct summary of the studies that demonstrated aerosols as a media of AMR transport in the atmosphere, strengthening the need to biomonitor these pernicious pollutants. This review will be a useful resource for environmental researchers, healthcare practitioners, and policymakers to issue related health advisories.

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.