Antibiotic resistance patterns of methicillin-resistant Staphylococcus aureus (MRSA) isolated from livestock and associated farmers in Anuradhapura, Sri Lanka

Antibiotic resistance through the lens of One Health: A study from an urban and a rural area in Sri Lanka

This study aimed to investigate and compare the proportion of AMR Escherichia coli (E. coli) between urban (Dompe in the Western province) and rural (Dambana in the Sabaragamuwa province) areas in Sri Lanka. The overall hypothesis of the study is that there is a difference in the proportion of AMR E. coli between the urban and the rural areas. Faecal samples were collected from healthy humans (n = 109), dairy animals (n = 103), poultry (n = 35), wild mammals (n = 81), wild birds (n = 76), soil (n = 80) and water (n = 80) from both areas. A total of 908 E. coli isolates were tested for susceptibility to 12 antimicrobials. Overall, E. coli isolated from urban area was significantly more likely to be resistant than those isolated from rural area. The human domain of the area had a significantly higher prevalence of AMR E. coli, but it was not significantly different in urban (98%) and rural (97%) areas. AMR E. coli isolated from dairy animals, wild animals and water was significantly higher in the urban area compared with the rural area. There was no significant difference in the proportion of multidrug resistance (MDR) E. coli isolated from humans, wild animals and water between the two study sites. Resistant isolates found from water and wild animals suggest contamination of the environment. A multi-sectorial One Health approach is urgently needed to control the spread of AMR and prevent the occurrences of AMR in Sri Lanka.

Kinship analysis of mecA gene of methicillin-resistant Staphylococcus aureus isolated from milk and risk factors from the farmers in Blitar, Indonesia

Background and Aim

There are numerous reports of subclinical mastitis cases in Blitar, which is consistent with the region's high milk production and dairy cattle population. Staphylococcus aureus, which is often the cause of mastitis cases, is widely known because of its multidrug-resistant properties and resistance to β-lactam antibiotic class, especially the methicillin-resistant S. aureus (MRSA) strains. This study aimed to molecular detection and sequence analysis of the mecA gene in milk and farmer's hand swabs to show that dairy cattle are reservoirs of MRSA strains.

Materials and Methods

A total of 113 milk samples and 39 farmers' hand swab samples were collected from a dairy farm for the isolation of S. aureus using Mannitol salt agar. The recovered isolates were further characterized using standard microbiological techniques. Isolates confirmed as S. aureus were tested for sensitivity to antibiotics. Oxacillin Resistance Screening Agar Base testing was used to confirm the presence of MRSA, whereas the mecA gene was detected by polymerase chain reaction and sequencing.

Results

A total of 101 samples were confirmed to be S. aureus. There were 2 S. aureus isolates that were multidrug-resistant and 14 S. aureus isolates that were MRSA. The mecA gene was detected in 4/14 (28.6%) phenotypically identified MRSA isolates. Kinship analysis showed identical results between mecA from milk and farmers' hand swabs. No visible nucleotide variation was observed in the two mecA sequences of isolates from Blitar, East Java.

Conclusion

The spread of MRSA is a serious problem because the risk of zoonotic transmission can occur not only to people who are close to livestock in the workplace, such as dairy farm workers but also to the wider community through the food chain.

Review of antibiotic use and resistance in food animal production in WHO South-East Asia Region

Antimicrobial resistance is an emerging global threat to public health. The resistant bacteria in food animals can be transferred to humans through the food chain. Limited information on antimicrobial usage and resistance in food animals is available in Southeast Asia due to inadequate monitoring or surveillance systems. A literature review was conducted on antimicrobial use and resistance in food animal production in Southeast Asia for the period 2011-2020, to assess the scope and extent of antibiotic use and resistance. The countries included in the study were Bangladesh, Bhutan, Democratic People's Republic of Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand and Timor-Leste. The information was categorised by country, production type and findings regarding antibiotic use and resistance. A total of 108 publications were included in the review. Results showed widespread use of critically and highly important antibiotics in livestock, poultry and aquacultured fish and their products. To curb the growing threat of antibiotic resistance, Southeast Asian countries need to strengthen surveillance and regulatory controls of antimicrobial use in food animal production through "One Health" approach.

Zoonotic sources and the spread of antimicrobial resistance from the perspective of low and middle-income countries

BACKGROUND

Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is widespread in these countries and is linked to an increased mortality. Apart from human and environmental factors, animal-related drivers of antimicrobial resistance in low- and middle-income countries have special features that differ from high-income countries. The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low- and middle-income countries.

MAIN BODY

Contamination with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is highest in poultry (Africa: 8.9-60%, Asia: 53-93%) and there is a risk to import ESBL-producing E. coli through poultry meat in Africa. In aquacultures, the proportion of ESBL-producers among E. coli can be high (27%) but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health. ESBL-producing E. coli colonization of wildlife is 1-9% in bats or 2.5-63% birds. Since most of them are migratory animals, they can disperse antimicrobial resistant bacteria over large distances. So-called 'filth flies' are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor. In Africa, up to 72.5% of 'filth flies' are colonized with ESBL-producing E. coli, mostly conferred by CTX-M (24.4-100%). While methicillin-resistant Staphylococcus aureus plays a minor role in livestock in Africa, it is frequently found in South America in poultry (27%) or pork (37.5-56.5%) but less common in Asia (poultry: 3%, pork: 1-16%).

CONCLUSIONS

Interventions to contain the spread of AMR should be tailored to the needs of low- and middle-income countries. These comprise capacity building of diagnostic facilities, surveillance, infection prevention and control in small-scale farming.

Evolution and implementation of One Health to control the dissemination of antibiotic-resistant bacteria and resistance genes: A review

Antibiotic resistance is a serious threat to humanity and its environment. Aberrant usage of antibiotics in the human, animal, and environmental sectors, as well as the dissemination of resistant bacteria and resistance genes among these sectors and globally, are all contributing factors. In humans, antibiotics are generally used to treat infections and prevent illnesses. Antibiotic usage in food-producing animals has lately emerged as a major public health concern. These medicines are currently being utilized to prevent and treat infectious diseases and also for its growth-promoting qualities. These methods have resulted in the induction and spread of antibiotic resistant infections from animals to humans. Antibiotics can be introduced into the environment from a variety of sources, including human wastes, veterinary wastes, and livestock husbandry waste. The soil has been recognized as a reservoir of ABR genes, not only because of the presence of a wide and varied range of bacteria capable of producing natural antibiotics but also for the usage of natural manure on crop fields, which may contain ABR genes or antibiotics. Fears about the human health hazards of ABR related to environmental antibiotic residues include the possible threat of modifying the human microbiota and promoting the rise and selection of resistant bacteria, and the possible danger of generating a selection pressure on the environmental microflora resulting in environmental antibiotic resistance. Because of the connectivity of these sectors, antibiotic use, antibiotic residue persistence, and the existence of antibiotic-resistant bacteria in human-animal-environment habitats are all linked to the One Health triangle. The pillars of support including rigorous ABR surveillance among different sectors individually and in combination, and at national and international level, overcoming laboratory resource challenges, and core plan and action execution should be strictly implemented to combat and contain ABR under one health approach. Implementing One Health could help to avoid the emergence and dissemination of antibiotic resistance while also promoting a healthier One World. This review aims to emphasize antibiotic resistance and its regulatory approaches from the perspective of One Health by highlighting the interconnectedness and multi-sectoral nature of the human, animal, and environmental health or ill-health facets.

Prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus isolates from retail raw meats in Turkey

The transmission of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) through food products of animal origin may pose a public health concern. Therefore, the objectives of the present work were to determine the prevalence of S. aureus and MRSA in raw meat samples (beef, chicken, turkey, and duck) at retail level, and to determine the antimicrobial resistance profile of the MRSA isolates. Between September 2018 and January 2019, a total of 325 raw meat samples were collected from retail stores, and analysed for the presence of S. aureus and MRSA using primary enrichment method as well as using secondary selective enrichment methods for MRSA detection. All the suspected S. aureus and MRSA colonies obtained from the samples were confirmed by both phenotypic and genotypic methods. The MRSA isolates were tested against various antimicrobials, and the minimal inhibitory concentration (MIC) of vancomycin was determined. Macrolide-lincosamide-streptogramin B (MLSB) resistance phenotypes were also screened using the double-disk diffusion test. The overall prevalence of S. aureus was 57.2%, whereas the food-specific prevalence in beef, turkey, duck, and chicken samples was 75, 53, 48, and 46%, respectively. The overall prevalence of MRSA was 1.2%, whereas it was 3, 1, 0, and 0% in beef, turkey, chicken, and duck samples, respectively. All MRSA isolates were detected by the secondary selective enrichment method. These MRSA isolates had a variety of MLSB resistance phenotypes (i.e., iMLSB, cMLSB, and MS-MLSB) with vancomycin MIC values ranging between 1 - 2 µg/mL. These findings are important for developing interventions to reduce raw meat contamination with S. aureus and MRSA, and to improve public health.

Genomic and Therapeutic Analyses of Staphylococcus aureus Isolated from Cattle Reproductive Tract

Staphylococcus aureus is emerging as a ubiquitous multidrug-resistant pathogen circulating among animals, humans, and their environment. The current study focused on molecular epidemiology and evidence-based treatment against S. aureus from bovine endometritis. For this study, n = 304 cattle were screened for endometritis using ultrasonography while presenting case history, and clinical signs were also considered. S. aureus was isolated from endometritis-positive uterine samples which were further put to molecular identification, phylogenetic analysis, susceptibility to antibiotics, and testing of novel drug combinations in both in vitro and field trials. The findings of the study revealed 78.20% of bovine endometritis samples positive for S. aureus, while nuc gene-based genotyping of S. aureus thermal nuclease (SA-1, SA-2, and SA-3) showed close relatedness with S. aureus thermal nuclease of Bos taurus. Drug combinations showed 5.00 to 188.88% rise in zones of inhibitions (ZOI) for drugs used in combination compared to the drugs used alone. Gentamicin in combination with amoxicillin and enrofloxacin with metronidazol showed synergistic interactions in an in vitro trial. Co-amoxiclav with gentamicin, gentamicin with enrofloxacin, and metronidazole with enrofloxacin showed 100%, 80%, and 60% efficacy in treating clinical cases in field trials, respectively. As a result, the study came to the conclusion the higher prevalence of endometritis-based S. aureus, genetic host shifts, narrow options for single drugs, and need for novel drug combinations to treat clinical cases.

Transmission routes of antibiotic resistant bacteria: a systematic review

Background

Quantification of acquisition routes of antibiotic resistant bacteria (ARB) is pivotal for understanding transmission dynamics and designing cost-effective interventions. Different methods have been used to quantify the importance of transmission routes, such as relative risks, odds ratios (OR), genomic comparisons and basic reproduction numbers. We systematically reviewed reported estimates on acquisition routes’ contributions of ARB in humans, animals, water and the environment and assessed the methods used to quantify the importance of transmission routes.

Methods

PubMed and EMBASE were searched, resulting in 6054 articles published up until January 1st, 2019. Full text screening was performed on 525 articles and 277 are included.

Results

We extracted 718 estimates with S. aureus (n = 273), E. coli (n = 157) and Enterobacteriaceae (n = 99) being studied most frequently. Most estimates were derived from statistical methods (n = 560), mainly expressed as risks (n = 246) and ORs (n = 239), followed by genetic comparisons (n = 85), modelling (n = 62) and dosage of ARB ingested (n = 17). Transmission routes analysed most frequently were occupational exposure (n = 157), travelling (n = 110) and contacts with carriers (n = 83). Studies were mostly performed in the United States (n = 142), the Netherlands (n = 87) and Germany (n = 60). Comparison of methods was not possible as studies using different methods to estimate the same route were lacking. Due to study heterogeneity not all estimates by the same method could be pooled.

Conclusion

Despite an abundance of published data the relative importance of transmission routes of ARB has not been accurately quantified. Links between exposure and acquisition are often present, but the frequency of exposure is missing, which disables estimation of transmission routes’ importance. To create effective policies reducing ARB, estimates of transmission should be weighed by the frequency of exposure occurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07360-z.

Methicillin-Resistant Staphylococcus aureus from Peninsular Malaysian Animal Handlers: Molecular Profile, Antimicrobial Resistance, Immune Evasion Cluster and Genotypic Categorization

Staphylococcus aureus (S. aureus) infections, particularly methicillin-resistant Staphylococcus aureus (MRSA) in humans and animals, have become a significant concern globally. The present study aimed to determine the prevalence and antibiogram of S. aureus isolated from animal handlers in Peninsular Malaysia. Furthermore, the genotypic characteristics of S. aureus isolates were also investigated. Nasal and oral swab samples were collected from 423 animal handlers in Peninsular Malaysia. The antibiogram profiles of S. aureus against 18 antibiotics were established using a Kirby–Bauer test. The genotypic profile of S. aureus, including the presence of antimicrobial resistance (AMR), virulence genes and spa genotypes, was investigated using molecular techniques. The overall carriage rate of S. aureus, MRSA and MDRSA was 30.5%, 1.2% and 19.4%, respectively. S. aureus was highly resistant against penicillin (72.3%) and amoxicillin (52.3%). Meanwhile, gentamicin and linezolid were fully effective against all the isolated S. aureus from animal handlers. It was observed that animal handlers with close exposure to poultry were more likely to carry S. aureus that is resistant to tetracycline and erythromycin. S. aureus isolates harboured tetracycline resistance (tetK, tetL and tetM), erythromycin resistance (ermA, ermB, ermC and msrA) and immune evasion cluster (IEC) genes (scn, chp, sak, sea and sep). Seventeen different spa types were detected among the 30 isolates of MDRSA, with t189 (16.7%) and t4171 (16.7%) being the predominant spa type, suggesting wide genetic diversity of the MDRSA isolates. The present study demonstrated the prevalence of S. aureus strains, including MRSA and MDRSA with various antimicrobial resistance and genetic profiles from animal handlers in Peninsular Malaysia.

Staphylococcus aureus in poultry, with special emphasis on methicillin-resistant strain infection: A comprehensive review from one health perspective

Staphylococcus aureus is a Gram-positive coccus normally present on the skin and internal organs of animals, birds, and humans. Under certain conditions, S. aureus could produce septicemia and affection of the skin, joints, and heart, as well as sepsis and death. The pathogenicity of S. aureus is associated with the presence of some virulent surface proteins and the production of some virulent toxins and enzymes. This pathogen is considered one of the most important and worldwide foodborne causes as it is incriminated in most cases of food poisoning. The hazardous use of antibiotics in the veterinary field leads to the development of multidrug-resistant S. aureus strains that can be transmitted to humans. The incidence of methicillin-resistant S. aureus (MRSA) strains has increased globally. These resistant strains have been detected in live animals, poultry, and humans. In addition, retail animal products, especially those of avian origin, are considered the main source of MRSA strains that can be easily transmitted to humans. MRSA infection is regarded as nosocomial or occupational. Humans get infected with MRSA strains through improper handling or preparation of contaminated animals or poultry carcasses or improper cooking with contaminated meat. Live birds also can transmit MRSA to close-contact workers in poultry farms. Transmission of MRSA infection in hospitals is from an infected individual to a healthy one. Prevention and control of MRSA are based on the application of hygienic measures in farms as well as proper processing, handling, and cooking of retail poultry products. The cooperation between veterinary and human practitioners is a must to avoid the possibility of zoonotic transmission. Accordingly, this review focused on the sources and transmission of MRSA infection, virulence and resistance factors, incidence and prevalence in poultry and different products, antibiotic resistance, and prevention and control strategies.

Ecology and Genetic Lineages of Nasal Staphylococcus aureus and MRSA Carriage in Healthy Persons with or without Animal-Related Occupational Risks of Colonization: A Review of Global Reports

In this conceptual review, we thoroughly searched for appropriate English articles on nasal staphylococci carriage among healthy people with no reported risk of colonization (Group A), food handlers (Group B), veterinarians (Group C), and livestock farmers (Group D) published between 2000 and 2021. Random-effects analyses of proportions were performed to determine the pooled prevalence of S. aureus, MRSA, MRSA-CC398, and MSSA-CC398, as well as the prevalence of PVL-positive S. aureus from all eligible studies. A total of 166 eligible papers were evaluated for Groups A/B/C/D (n = 58/31/26/51). The pooled prevalence of S. aureus and MRSA in healthy humans of Groups A to D were 15.9, 7.8, 34.9, and 27.1%, and 0.8, 0.9, 8.6, and 13.5%, respectively. The pooled prevalence of MRSA-CC398 nasal carriage among healthy humans was as follows: Group A/B (<0.05%), Group C (1.4%), Group D (5.4%); and the following among Group D: pig farmers (8.4%) and dairy farmers (4.7%). The pooled prevalence of CC398 lineage among the MSSA and MRSA isolates from studies of the four groups were Group A (2.9 and 6.9%), B (1.5 and 0.0%), C (47.6% in MRSA), and D (11.5 and 58.8%). Moreover, MSSA-CC398 isolates of Groups A and B were mostly of spa-t571 (animal-independent clade), while those of Groups C and D were spa-t011 and t034. The MRSA-CC398 was predominately of t011 and t034 in all the groups (with few other spa-types, livestock-associated clades). The pooled prevalence of MSSA and MRSA isolates carrying the PVL encoding genes were 11.5 and 9.6% (ranges: 0.0-76.9 and 0.0-28.6%), respectively. Moreover, one PVL-positive MSSA-t011-CC398 isolate was detected in Group A. Contact with livestock and veterinary practice seems to increase the risk of carrying MRSA-CC398, but not in food handlers. Thus, this emphasizes the need for integrated molecular epidemiology of zoonotic staphylococci.

Prevalence and Characteristics of Multidrug-Resistant Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA) CC398 Isolated from Quails (Coturnix Coturnix Japonica) Slaughtered for Human Consumption

Simple Summary

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in both humans and animals worldwide. MRSA associated with livestock is a zoonotic pathogen that has been reported in several animals and, although its infections in humans are rare, this strain is recognized as an occupational hazard for people working in direct contact with livestock. Thus, we aimed to isolate MRSA from quails and to characterize their antimicrobial resistance and genetic lineages. One hundred swab samples were recovered from quails at the slaughterhouse. To investigate the prevalence and antimicrobial resistance of MRSA in poultry, we conducted this study on 100 quails slaughtered for human consumption. The antimicrobial resistance was investigated in all isolates as well as virulence genes and genetic lineages. Twenty-nine MRSA were isolated. The results showed that all MRSA isolates had resistance to multiple antibiotics. All strains were classified as livestock-associated. Most strains belonged to a well-known livestock-associated lineage: CC398.

Abstract

Livestock-associated MRSA (LA-MRSA) is a zoonotic pathogen that has been reported in several animals, and it is often associated with clonal complex (CC) 398. We aimed to isolate MRSA from quails and to characterize their antimicrobial resistance and genetic lineages. One hundred swab samples were recovered from quails at the slaughterhouse. The swabs were inoculated onto CHROMagar™ MRSA agar plates for MRSA isolation. The presence of antimicrobial-resistant genes and virulence factors was investigated by PCR. All strains were typed by MLST, SCCmec-, spa- and agr-typing. From the 100 samples, 29 MRSA were isolated. All strains were resistant to penicillin, cefoxitin, ciprofloxacin, erythromycin and clindamycin and carried the blaZ, mecA, ermB and ermC genes. All strains, except one, showed resistance to tetracycline and harbored the tetM, tetK and tetL genes in different combinations. Twenty strains belonged to ST398 and SCCmec type V, and nine strains belonged to the new ST6831. Twenty-eight out of twenty-nine strains were ascribed to t011 and one to t108. As far as we know, this is the first report of MRSA from quails slaughtered for human consumption. Most strains belonged to ST398-t011, which is the most common LA-MRSA clone found in livestock in Europe.

Antimicrobial uses for livestock production in developing countries

Antimicrobial is an indispensable part of veterinary medicine used for the treatment and control of diseases as well as a growth promoter in livestock production. Frequent use of antimicrobials in veterinary practices may lead to the residue in animal originated products and creates some potential problems for human health. The presence of antimicrobial residues in animal originated foods may induce serious health problems such as allergic reaction, antimicrobial resistance (AMR), and lead to carcinogenic and mutagenic effects in the human body. The misuse or abuse of antibiotics in human medicine is thought to be a principal cause of AMR but some antimicrobial-resistant bacteria and their resistant genes originating from animals are also responsible for developing AMR. However, the residual effect of antimicrobials in feed and food products of animal origin is undeniable. In developing countries, the community is unaware of this residual effect due to lack of proper information about antibiotic usage, AMR surveillance, and residue monitoring system. It is imperative to reveal the current situation of antimicrobial use in livestock production and its impacts on public health. Moreover, the safety levels of animal feeds and food products of animal origin must be strictly monitored and public awareness should be developed against the indiscriminate use of antimicrobial in animal production. Therefore, the current review summarizes the literature on antimicrobial use in livestock production and its hazardous residual impacts on the human body in developing countries.

Multidrug-resistance in methicillin-resistant Staphylococcus aureus (MRSA) isolated from a subtropical river contaminated by nearby livestock industries

Methicillin-resistant Staphylococcus aureus (MRSA) is a major threat to public health that causes infections in hospitals, communities, and animal husbandry. Livestock-associated MRSA (LA-MRSA) is defined as MRSA possessing staphylococcal cassette chromosome mec (SCCmec) IV or V, both of which lacks the Panton-Valentine leukocidin (PVL) gene but has variable combinations of antimicrobial susceptibility. This study focused on Taiwan's subtropical river basin and the Puzih River, which converges from tributaries flowing through downtown and animal husbandry areas. MRSA was detected at a rate of 7.8% in the tributaries, which was higher than downstream (2.1%). The ratio of multidrug-resistant (MDR) MRSA (n = 30) to total MRSA isolates (n = 39) was 0.769, and most of the MDR MRSA isolates (66.7%, 20/30) exhibited resistance to chloramphenicol, ciprofloxacin, clindamycin, erythromycin, sulfamethoxazole-trimethoprim, and tetracycline. The number of MDR MRSA isolates in the tributaries was also higher than the downstream regions of the Puzih River. The majority of MRSA isolates (64.1%) observed in this study possessed SCCmec type IV without PVL, which is typical for LA-MRSA. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) typing aided the discrimination of resistance patterns among SCCmec types. This study highlights the threat to human health posed by the waterborne transmission of MDR LA-MRSA.

Asymptomatic central line-associated bloodstream infections in children implanted with long term indwelling central venous catheters in a teaching hospital, Sri Lanka

Background

Indwelling central venous catheters (CVC) are used to provide long term hemodialysis. The commonest and the severe complication of CVC is the central line-associated bloodstream infection (CLABSI). This study was done to assess the etiology and infectious complications of CVC in children on long term hemodialysis.

Methods

Children newly undergoing hemodialysis and having indwelling CVC were included. They were followed up to a period of 2-years to assess infectious complications. Catheter bundle care approach was employed to prevent infections and other complications. Automated culture from the central catheter and peripheral vein and 2D echocardiography were done in each hemodialysis. Serial procalcitonin (PCT) was measured. Differential time of positivity (DTP) was used to detect CLABSI. During homestay in weekly telephone conversations were done to assess features of infection, and whenever having, we have asked to admit to the tertiary care unit. Logistic regression was performed, and the significant outcome variable was considered following multivariable analysis as a risk factor.

Results

Blood cultures were positive in 1090 (74.5%) out of 1462 children. According to DTP, 410 (28%) were having CLABSI, while 520 (35.6%) were having bacteremia without CLABSI. Out of 410 CLABSI patients, 79 (19.2%) were asymptomatic. Coagulase-negative Staphylococcus spp. (CoNS) bacteremia was significantly associated with asymptomatic CLABSI. Right-sided infective endocarditis (RS-IE) was significantly associated with asymptomatic CLABSI and asymptomatic bacteremia without CLABSI. CoNS was associated significantly in RS-IE following asymptomatic CLABSI and asymptomatic bacteremia. PCT was in asymptomatic CLABSI was 1.8 ± 0.9 ng/mL while in symptomatic CLABSI was 11.3 ± 2.5 ng/ml (P = 0.02). CoNS bloodstream infection, tunneled CVC, peripherally inserted central catheter, femoral site, the number of line days > 90, receipt of vancomycin, meropenem, or linezolid in the 5 days before CLABSI diagnosis and recurrent bacteremia were risk factors for asymptomatic CLABSI.

Conclusions

Asymptomatic CLABSI could be a rare occurrence. CoNS was predominantly isolated in patients with asymptomatic CLABSI. RS- IE is a well-known complication in long term indwelling CVC. CoNS was significantly associated with RS-IE following asymptomatic CLABSI. Regular procalcitonin, microbiological, and imaging studies would be essential to detect infectious complications in both symptomatic and asymptomatic patients implanted with long term indwelling CVCs.

Natural brominated phenoxyphenols kill persistent and biofilm-incorporated cells of MRSA and other pathogenic bacteria

Due to a high unresponsiveness to chemotherapy, biofilm formation is an important medical problem that frequently occurs during infection with many bacterial pathogens. In this study, the marine sponge-derived natural compounds 4,6-dibromo-2-(2',4'-dibromophenoxy)phenol and 3,4,6-tribromo-2-(2',4'-dibromophenoxy)phenol were found to exhibit broad antibacterial activity against medically relevant gram-positive and gram-negative pathogens. The compounds were not only bactericidal against both replicating and stationary phase-persistent planktonic cells of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa; they also killed biofilm-incorporated cells of both species while not affecting biofilm structural integrity. Moreover, these compounds were active against carbapenemase-producing Enterobacter sp. This simultaneous activity of compounds against different growth forms of both gram-positive and gram-negative bacteria is rare. Genome sequencing of spontaneous resistant mutants and proteome analysis suggest that resistance is mediated by downregulation of the bacterial EIIBC phosphotransferase components scrA and mtlA in MRSA likely leading to a lower uptake of the molecules. Due to their only moderate cytotoxicity against human cell lines, phenoxyphenols provide an interesting new scaffold for development of antimicrobial agents with activity against planktonic cells, persisters and biofilm-incoporated cells of ESKAPE pathogens. KEY POINTS: • Brominated phenoxyphenols kill actively replicating and biofilm-incorporated bacteria. • Phosphotransferase systems mediate uptake of brominated phenoxyphenols. • Downregulation of phosphotransferase systems mediate resistance.

The relationship between the exposure to healthcare settings and colonization with methicillin-resistant Staphylococcus aureus among medical students

Introduction

Medical students who engage in clinical learning in healthcare settings can be potential methicillin-resistant Staphylococcus aureus (MRSA) carriers.

Methods

This is a descriptive cross-sectional study having a follow-up approach. Three batches of medical students who were studying at the Faculty of Medicine and Allied Sciences, Rajarata University of Sri Lanka (1^st, 3^rd and 5^th study years of MBBS course) were screened for nasal and axillary MRSA colonization. The first-year students were screened before and 6 months after clinical learning. The knowledge of the students about infection control was scored (percentage) using a questionnaire in the one week before and later one year after the hospital exposure. Data was compared using two-sample t test.

Results

The percentage of MRSA colonization was 6.36% (7/110) and 49.57% (59/119) before clinical exposure and after 2.5 years of exposure, respectively (p<0.012). The percentage of correct responses obtained by the students for the questionnaire about infection control was 28% and 66.9% one week before the exposure to the hospitals and one year after the exposure to the hospitals, consecutively.

Conclusions

MRSA carriage was significantly associated with the time duration of the clinical training of the medical students. The knowledge of students about infection control was significantly inadequate one week before the hospital exposure and they have gained the knowledge only after being exposed to the hospitals.

First mecC and mecA Positive Livestock-Associated Methicillin Resistant Staphylococcus aureus (mecC MRSA/LA-MRSA) from Dairy Cattle in Malaysia

Livestock associated Methicillin resistant Staphylococcus aureus (S. aureus) (LA-MRSA) was reported to be zoonotic and may transmit to farmers and veterinarians. The objectives of this study were to investigate the occurrence of LA-MRSA from dairy cattle and to evaluate the antimicrobial resistance profiles of the isolates. A total of 63 milk and 32 nasal swab samples were randomly collected from dairy cattle. The samples were processed to isolate S. aureus, MRSA and LA-MRSA using both phenotypic and molecular methods using PCR. The confirmed S. aureus isolates were cultured on oxacillin resistant screening agar base (ORSAB) to detect MRSA and the isolates were further confirmed by PCR targeting the mecA gene. Detection of the novel mecA gene, mecC gene was conducted by PCR amplification. The antimicrobial susceptibility tests were conducted using disc diffusion method. Results revealed 17/95 (17.89%) and 15/95 (15.79%) were positive for mecA and mecC genes respectively. Out of the 15 mecC positive isolates, 12 were positive for both mecA and mecC. The MRSA isolates showed multidrug resistance. The findings showed high prevalence of mecC-positive LA-MRSA in Malaysia and highlight the public health risks to people that may come in contact with the carrier animals or those who may consume unpasteurized milk products from these animals.

Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus in long-term care facilities in eastern Taiwan

Objective:

The prevention of infections is crucial in long-term care programs. Investigations of the occurrence and sources of pathogens in long-term care facilities (LTCFs) are still lacking, especially in eastern Taiwan. In this study, we conducted a surveillance of two common pathogens, Acinetobacter baumannii (AB) and methicillin-resistant Staphylococcus aureus (MRSA), in LTCFs in Hualien.

Materials and Methods:

Pathogenic assays including isolation, identification, and antimicrobial susceptibility tests were conducted for AB and MRSA at LTCFs in Eastern Taiwan. Staphylococcal cassette chromosome mec typing assays were done to understand the relatedness of clonal strains of MRSA.

Results:

All AB-positive samples in the LTCFs were mainly from water-rich samples and were drug susceptible. Our data indicated that the AB strains from LTCFs were similar to those from Puzi River watersheds in Taiwan, which were not drug resistant to commonly used antibiotics. On the other hand, the drug resistance analysis of MRSA indicated that the genotypes from the LTCFs were similar to those from nearby hospitals. Eight strains of MRSA were isolated from four LTCFs, of which five were identified as hospital-acquired strains according to SSCmed typing assays.

Conclusion:

These findings suggest that MRSA in LTCFs might propagate from hospitals and could be transmitted between hospitals and LTCFs. Health authorities should be aware of this risk. The long-term follow-up of MRSA is recommended in local medical institutions as well as in LTCFs for correlative analysis.

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage and pattern of antibiotic resistance among sheep farmers from Southern Italy

PURPOSE

We conducted a cross-sectional study to measure the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization, with a particular focus on livestock associated (LA)-MRSA in farmers working in contact with livestock (sheep) in one Italian region. Furthermore, we have assessed the antimicrobial resistance pattern of isolates and the association of carriage with specific characteristic of farms and working tasks.

PATIENTS AND METHODS

Demographic data, occupational history, and contact with animals information was collected. Nasal and oropharyngeal swabs were collected and all samples were tested for the isolation and identification of S. aureus. Isolates were examined for antimicrobial susceptibility and all MRSA strains underwent molecular analyses through multiple-locus variable number of tandem repeat analysis (MLVA).

RESULTS

A total of 115 sheep farms and 275 sheep farmers were enrolled. MRSA colonized workers were found in three farms; S. aureus was isolated in 97 workers (35.5%), whereas MRSA was isolated in 3 (1.1%) workers. All MRSA isolates were classified as multidrug resistant. Two of the MRSA isolates were resistant to quinupristin/dalfopristin (QDA), mupirocin, erythromycin, and tetracycline. Among methicillin-susceptible S. aureus (MSSA), 32 (34%) were resistant to tetracycline, 31 (33%) to erythromycin, 26 (27.6%) to QDA, and 22 (23.4%) to linezolid and clindamycin. One MRSA belonged to MLVA complex (MC) 001, found to colonize both humans and animals.

CONCLUSION

The picture of MRSA transmission among sheep farmers does not seem to be critical, although there is the need to improve adequate control measures to prevent and minimize any biological risk in sheep farms for both animal and human health. Specific monitoring/surveillance programs would help in better understanding the epidemiology of resistant strains.

The emergence of non-albicans candidemia and evaluation of HiChrome Candida differential agar and VITEK2 YST® platform for differentiation of Candida bloodstream isolates in teaching hospital Kandy, Sri Lanka

Background

Candidemia is an emerging hospital-acquired bloodstream infection (BSI). It is common among severely ill and immunocompromised patients. Even following appropriate therapy in candidemia, recent studies reveal relative high mortality (40%). The global incidence of candidemia shows an incline. In Sri Lanka, candida speciation often difficult where basic facilities are less available. We have compared the risk factors, epidemiology, demography, and performance of HiChrome Candida differential agar (HiCA) characteristics with the VITEK2 YST platform for differentiation of Candida albicans (CA) and non-albicans candida (NAC) from blood culture isolate.

Methods

This is a laboratory-based cross-sectional study. Positive aerobic BACTEC blood cultures having yeast were identified using HiCA and VITEK2® platform. Epidemiology, risk factors, and clinical outcomes were compared between CA and NAC bloodstream isolates.

Results

Out of 120 positive yeast samples, VITEK2® has identified 110 (92%) as Candida sp. From that CA-34 (31%) and NAC-76 (69%) were isolated. Candidemia following NCA in neonates (p = 0.02), infants (p = 0.04) and adults (p = 0.02) in ICU and immunocompromised patients were significantly higher. Compared to CA, NAC bacteremia period prevalence (0.00041%) and incidence (0.23 per 100,000-person-years) was significantly high (p = 0.03). NAC 48 (63%) isolates were resistance to azoles. Exposure to antifungals (odds ratio (OR); p = 0.03), prolonged intensive care stay > 14 days (OR-3.3; p = 0.04), having a central venous line for > 8 days (OR-4.3; p = 0.03) and on immunosuppressive treatment (OR-2.4; p = 0.04) was significantly poses risk for NAC candidemia. Sen day mortality was significant among non-albicans cases (p = 0.03) while 30-day mortality was significant among albicans cases (p = 0.04). Compared to VITEK2®, the HiCA method was 93% sensitive and 93% specific in detecting CA.

Conclusion

Compared to CA, candidemia following NAC was high. NAC isolates were having a high percentage of fluconazole and voriconazole resistance. VITEK2 YST® platform provides antifungal susceptibility with minimal inhibitory concentration (MIC). Impact, this would highlight the use of rapid candida identification flat form with MIC to direct appropriate antifungals for candidemia. For that implementation of novel diagnostic facilities like the VITEK2 YST platform at a tertiary care facility is demanding.

Genomic and Epidemiological Evidence of a Dominant Panton-Valentine Leucocidin-Positive Methicillin Resistant Staphylococcus aureus Lineage in Sri Lanka and Presence Among Isolates From the United Kingdom and Australia

Objective: To undertake the first detailed genomic analysis of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Sri Lanka. Methods: A prospective observational study was performed on 94 MRSA isolates collected over a 4 months period from the Anuradhapura Teaching Hospital, Sri Lanka. Screening for mecA, mecC, and the Panton-Valentine leucocidin (PVL)-associated lukS-PV/lukF-PV genes and molecular characterization by spa typing was undertaken. Whole genome sequencing (WGS) and phylogenetic analysis was performed on selected multilocus sequence type (MLST) clonal complex 5 (CC5) isolates from Sri Lanka, England, Australia, and Argentina. Results: All 94 MRSA harbored the mecA gene. Nineteen spa types belonging to nine MLST clonal complexes were identified. Where origin of the sample was recorded, most isolates were from skin and soft tissue infections (70/91; 76.9%), with fewer causing bacteremia (16/91; 17.6%), empyema (3/91; 3.3%) and osteomyelitis (2/91; 2.2%). Sixty two (65.9%) isolates were PVL positive with the majority (56 isolates; 90.3%) belonging to a dominant CC5 lineage. This lineage, PVL-positive ST5-MRSA-IVc, was associated with both community and hospital-onset infections. Based on WGS, representative PVL-positive ST5-MRSA-IVc isolates from Sri Lanka, England and Australia formed a single phylogenetic clade, suggesting wide geographical circulation. Conclusions: We present the most detailed genomic analysis of MRSA isolated in Sri Lanka to date. The analysis identified a PVL-positive ST5-MRSA-IVc that is prevalent among MRSA causing clinical infections in Sri Lanka. Furthermore, this clone was also found among isolates from the United Kingdom and Australia.

Antimicrobial misuse in pediatric urinary tract infections: recurrences and renal scarring

Background

In children, urinary tract infection (UTI) is one of a common bacterial infection. This study was conducted to detect the uropathogen, antimicrobial susceptibility, pathogen associated with recurrences and renal scarring in children initially taken care from general practitioners and later presented to tertiary care.

Methods

Every inward UTI episode, culture and antimicrobial susceptibility was done while on past 6-month, history of infections and use of antimicrobials was collected using clinical records and demonstration of antimicrobials. Children with recurrent pyelonephritis was followed and in vitro bio film formation was assessed.

Results

Frequency of UTI was significantly high among infants (p = 0.03). Last 6-month, all (220) were exposed to antimicrobials. Cefixime was the commonly prescribed antimicrobial (p = 0.02). In current UTI episode, 64.5% (142/220) of children with UTI were consulted GPs’ prior to seek treatment from tertiary care pediatric unit (p = 0.02). While on follow up child who developed UTI, found urine culture isolates were significantly shifted from E. coli and K. pneumoniae to extended spectrum of beta-lactamase (ESBL) E. coli and K. pneumoniae. Out of 208 participants, 36 of them had re-current pyelonephritis (R-PN). Renal scarring (RS) was detected in 22 out of 70 patients with pyelonephritis following dimercaptosuccinic acid scan. Following each episodes of recurrent pyelonephritis 11% of new scar formation was detected (p = 0.02). Bio film forming E. coli and K. pneumoniae was significantly associated in patients with R-PN (p = 0.04).

Discussion

Medical care providers often prescribe antimicrobials without having an etiological diagnosis. While continuing exposure of third generation cephalosporin and carbapenem leads to development of ESBL and CRE microbes in great. The empiric uses of antimicrobials need to be stream lined with local epidemiology and antimicrobial susceptibility pattern. R-PN in childhood leads to RS. In great, bio film formation act as the focus for such recurrences.