Prevalence of methicillin-resistant Staphylococcus aureus in healthy Chinese population: A system review and meta-analysis

ESKAPE in China: epidemiology and characteristics of antibiotic resistance

The escalation of antibiotic resistance and the diminishing antimicrobial pipeline have emerged as significant threats to public health. The ESKAPE pathogens - Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. - were initially identified as critical multidrug-resistant bacteria, demanding urgently effective therapies. Despite the introduction of various new antibiotics and antibiotic adjuvants, such as innovative β-lactamase inhibitors, these organisms continue to pose substantial therapeutic challenges. People's Republic of China, as a country facing a severe bacterial resistance situation, has undergone a series of changes and findings in recent years in terms of the prevalence, transmission characteristics and resistance mechanisms of antibiotic resistant bacteria. The increasing levels of population mobility have not only shaped the unique characteristics of antibiotic resistance prevalence and transmission within People's Republic of China but have also indirectly reflected global patterns of antibiotic-resistant dissemination. What's more, as a vast nation, People's Republic of China exhibits significant variations in the levels of antibiotic resistance and the prevalence characteristics of antibiotic resistant bacteria across different provinces and regions. In this review, we examine the current epidemiology and characteristics of this important group of bacterial pathogens, delving into relevant mechanisms of resistance to recently introduced antibiotics that impact their clinical utility in China.

Epidemiology of Antimicrobial Resistance Genes in Staphylococcus aureus Isolates from a Public Database from a One Health Perspective-Sample Origin and Geographical Distribution of Isolates

Staphylococcus aureus are commensal bacteria that are found in food, water, and a variety of settings in addition to being present on the skin and mucosae of both humans and animals. They are regarded as a significant pathogen as well, with a high morbidity that can cause a variety of illnesses. The Centers for Disease Control and Prevention (CDC) has listed them among the most virulent and resistant to antibiotics bacterial pathogens, along with Escherichia coli, Staphylococcus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus faecalis, and Enterococcus faecium. Additionally, S. aureus is a part of the global threat posed by the existence of antimicrobial resistance (AMR). Using 26,430 S. aureus isolates from a global public database (NPDIB; NCBI Pathogen Detection Isolate Browser), epidemiological research was conducted. The results corroborate the evidence of notable variations in isolate distribution and ARG (Antimicrobial Resistance Gene) clusters between isolate sources and geographic origins. Furthermore, a link between the isolates from human and animal populations is suggested by the ARG cluster patterns. This result and the widespread dissemination of the pathogens among animal and human populations highlight how crucial it is to learn more about the epidemiology of these antibiotic-resistance-related infections using a One Health approach.

Identification of Vancomycin Resistance in Methicillin-resistant Staphylococcus aureus in two macaque species and decolonization and long-term prevention of recolonization in Cynomolgus Macaques (Macaca fascicularis)

Methicillin-resistant Staphylococcus aureus (MRSA) is a S. aureus strain with resistance to beta-lactam antibiotics, making it a global human and veterinary health concern. Specifically, immunosuppressed patients have a remarkably higher risk of clinical MRSA infections with significantly increased rates of prolonged clinical recovery, morbidity, and mortality. The current treatment of choice for MRSA is vancomycin. Importantly, we report the first known vancomycin-resistant S. aureus (VRSA) carriers in a cohort of Mauritian cynomolgus macaques (CM) imported to the Oregon National Primate Research Center (ONPRC), with a MRSA carrier rate of 76.9% (10/13 animals). All MRSA isolates also demonstrated resistance to vancomycin with prevalence of vancomycin-intermediate Staphylococcus aureus (VISA) at 30% (3/10 MRSA-positive CMs) and VRSA at 70% (7/10 MRSA-positive CMs). Additionally, we identified VRSA in a rhesus macaque (RM) housed within the same room as the VRSA-positive CMs and identified a MRSA/VISA carrier rate of 18.8% in RMs (3/16 positive for both MRSA and VISA) in unexposed recently assigned animals directly from the ONPRC RM breeding colony. Considering that the MRSA and VRSA/VISA-positive CMs future study aims included significant immunosuppression, MRSA/VRSA/VISA decolonization treatment and expanded "MRSA-free" practices were employed to maintain this status. We report the first controlled study using in-depth analyses with appropriate diagnostic serial testing to definitively show an MRSA decolonization therapy (90% success rate) and expanded barrier practice techniques to successfully prevent recolonization (100%) of a cohort of CMs MRSA-free (up to 529 days with a total of 4,806 MRSA-free NHP days).

Antimicrobial Resistant Staphylococcus Species Colonization in Dogs, Their Owners, and Veterinary Staff of the Veterinary Teaching Hospital of Naples, Italy

This study aimed to identify Staphylococcus species isolated from nasal swabs of both healthy and diseased dogs, and those of human origin, obtained from nasal swabs of both owners and veterinary staff. Firstly, pet owners were requested to complete a questionnaire relating to the care and relationship with their pets, whose results mainly showed a statistically significant higher frequency of hand washing in diseased dogs' owners than in healthy dogs' owners. Canine nasal swabs were obtained from 43 diseased dogs and 28 healthy dogs, while human nasal swabs were collected from the respective dogs' owners (71 samples) and veterinary staff (34 samples). The isolation and identification of Staphylococcus spp. were followed by disk diffusion method to define the antimicrobial resistance profiles against 18 different molecules. Staphylococcus pseudintermedius was the most frequent isolated strain in both diseased (33.3%) and healthy (46.1%) dogs. Staphylococcus epidermidis was the most frequent isolated bacterium in diseased dogs' owners (66.6%), while in nasal samples of healthy dogs' owners, the same frequency of isolation (38.4%) was observed for both Staphylococcus epidermidis and Staphylococcus aureus. All the isolated strains showed good susceptibility levels to the tested antimicrobials; however, the carriage of oxacillin-resistant strains was significantly higher in diseased dogs than in healthy ones (71% and 7.7%, respectively). Only in three cases the presence of the same bacterial species with similar antimicrobial resistance profiles in dogs and their owners was detected, suggesting the potential bacterial transmission. In conclusion, this study suggests potential transmission risk of staphylococci from dogs to humans or vice versa, and highlights that the clinical relevance of Staphylococcus pseudintermedius transmission from dog to human should not be underestimated, as well as the role of Staphylococcus aureus from human to dog transmission.

Bacterial isolates and their antimicrobial susceptibility profile of superficial and deep-seated skin and soft tissue infections

Background

Skin and soft tissue infections (SSTIs) are caused by microbial invasion of healthy or damaged skin. SSTIs are difficult to manage and contribute to chronicity and emergence of antimicrobial resistance.

Objectives

To ascertain the prevalence of bacteria causing SSTIs and their antimicrobial susceptibility patterns.

Methods

A prospective study between November 2020 and May 2021. A total of 447 samples from SSTIs were analyzed.

Results

A total of 347 samples revealed mono-bacterial growth, of which 67% were male. SSTIs are common among patients aged 21-50 years with the dominance (78%) of gram-negative rods (GNRs). Escherichia coli (36%), Klebsiella spp. (22%), Staphylococcus aureus (16%), and Pseudomonas aeruginosa (11%) were predominant organisms. GNRs were highly resistant (>65%) to ciprofloxacin and trimethoprim-sulfamethoxazole. For injectable antibiotics, the highest resistance was determined against ceftriaxone, and the least resistance was determined against amikacin. Resistance against carbapenem was the highest among P. aeruginosa (53%) and Klebsiella spp. (32%). S. aureus showed the highest resistance against ciprofloxacin, and the least resistance was determined against clindamycin. Of 57 S. aureus isolates, 86% isolates were methicillin-resistant Staphylococcus aureus (MRSA). All isolates of P. aeruginosa and S. aureus were sensitive to polymyxin B and vancomycin, respectively. The prevalence of multidrug-resistant E. coli and Klebsiella spp. was higher among deep-seated SSTIs (dSSTIs).

Conclusions

The predominant etiology of SSTIs is GNR. Currently, there is very high resistance against oral antibiotics. Antimicrobial resistance against carbapenem has also increased. Moreover, there is a high frequency of MRSA. MDR E. coli and Klebsiella spp. isolates are frequently involved in dSSTIs.

A Novel Strategy to Identify Endolysins with Lytic Activity against Methicillin-Resistant Staphylococcus aureus

The increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the dairy industry has become a fundamental concern. Endolysins are bacteriophage-derived peptidoglycan hydrolases that induce the rapid lysis of host bacteria. Herein, we evaluated the lytic activity of endolysin candidates against S. aureus and MRSA. To identify endolysins, we used a bioinformatical strategy with the following steps: (1) retrieval of genetic information, (2) annotation, (3) selection of MRSA, (4) selection of endolysin candidates, and (5) evaluation of protein solubility. We then characterized the endolysin candidates under various conditions. Approximately 67% of S. aureus was detected as MRSA, and 114 putative endolysins were found. These 114 putative endolysins were divided into three groups based on their combinations of conserved domains. Considering protein solubility, we selected putative endolysins 117 and 177. Putative endolysin 117 was the only successfully overexpressed endolysin, and it was renamed LyJH1892. LyJH1892 showed potent lytic activity against both methicillin-susceptible S. aureus and MRSA and showed broad lytic activity against coagulase-negative staphylococci. In conclusion, this study demonstrates a rapid strategy for the development of endolysin against MRSA. This strategy could also be used to combat other antibiotic-resistant bacteria.

Differences in characteristics, aetiologies, isolated pathogens, and the efficacy of antibiotics in adult patients with preseptal cellulitis and orbital cellulitis between 2000-2009 and 2010-2019

BACKGROUND/AIMS

To understand whether the epidemiology, aetiologies, common pathogens and the antibiotic efficacy against the identified bacteria of periorbital cellulitis in adults have changed recently (2010-2019) compared with the past decade (2000-2009).

METHODS

Adult patients (n=224) diagnosed with preseptal cellulitis and orbital cellulitis admitted to Kaohsiung Veterans General Hospital during 2000-2019 were retrospectively reviewed. Demographic and clinical characteristics, isolated pathogens and antibiotic susceptibility tests against the commonly cultured bacteria were analysed.

RESULTS

Preseptal cellulitis showed a tendency of female predominance. Patients in their 60s showed an incidence peak; more cases were observed during winter. The most common predisposing factor was dacryocystitis (15.5%-30.5%), followed by hordeolum (15.5%-24.8%). Aetiology of sinusitis (p=0.001) decreased and that of conjunctivitis (p=0.007) increased significantly with time. Culture results of nasopharyngeal swabs and local abscess showed higher positivity rate than conjunctival swab. The most common isolates were methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, coagulase-negative staphylococci and Pseudomonas aeruginosa. Antibiotics including fluoroquinolones and vancomycin were effective; in contrast, ampicillin/sulbactam and oxacillin showed decreasing efficacy against gram-positive bacteria. For antibiotic treatment against P. aeruginosa, fluoroquinolones, ceftazidime, piperacillin and imipenem were ideal choices.

CONCLUSION

In isolated pathogens, the increasing trend of methicillin-resistant S. aureus detection was compatible with reducing oxacillin efficacy against periorbital infection. In our study, the report of antibiotic efficacy against the most common identified bacteria offered empirical choices for hospitalised patients with periorbital infection before obtaining culture results.

Systematic analysis of lysine crotonylation in human macrophages responding to MRSA infection

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly encountered bacteria found in healthcare clinics and has been ranked a priority 2 pathogen. Research is urgently needed to develop new therapeutic approaches to combat the pathogen. Variations in the pattern of protein posttranslational modifications (PTMs) of host cells affect physiological and pathological events, as well as therapeutic effectiveness. However, the role of crotonylation in MRSA-infected THP1 cells remains unknown. In this study, we found that crotonylation profiles of THP1 cells were altered after MRSA infection. It was then confirmed that lysine crotonylation profiles of THP1 cells and bacteria were different; MRSA infection inhibited global lysine crotonylation (Kcro) modification but partially elevated Kcro of host proteins. We obtained a proteome-wide crotonylation profile of THP1 cells infected by MRSA further treated by vancomycin, leading to the identification of 899 proteins, 1384 sites of which were down-regulated, and 160 proteins with 193 sites up-regulated. The crotonylated down-regulated proteins were mainly located in cytoplasm and were enriched in spliceosome, RNA degradation, protein posttranslational modification, and metabolism. However, the crotonylated up-regulated proteins were mainly located in nucleus and significantly involved in nuclear body, chromosome, ribonucleoprotein complex, and RNA processing. The domains of these proteins were significantly enriched on RNA recognition motif, and linker histone H1 and H5 families. Some proteins related to protecting against bacterial infection were also found to be targets of crotonylation. The present findings point to a comprehensive understanding of the biological functions of lysine crotonylation in human macrophages, thereby providing a certain research basis for the mechanism and targeted therapy on the immune response of host cells against MRSA infection.

Detection of Methicillin Resistance and β-Lactamase Production in Staphylococcus aureus Isolates: A Cross Sectional Study from a Tertiary Care Hospital

Nosocomial infections are proving to be a menace for the whole health care system, with methicillin resistant Staphylococcus aureus (MRSA) being a very notorious causative agent. Along with the role of mecA gene producing penicillin-binding protein (PBP2a), production of beta-lactamase enzyme by Staphylococcus aureus makes the organism resistant to all β-lactam agents. This study aims at phenotypic detection of methicillin resistance and β-Lactamase production in all S. aureus isolates by Cefoxitin disk diffusion test and Penicillin zone-edge test, respectively. In this prospective cross-sectional study, samples were obtained from patients admitted to different departments and were processed according to the standard laboratory protocols. As per the CLSI guidelines, phenotypic detection of resistance to methicillin was done by Cefoxitin Disk Diffusion test, whereas production of beta-lactamase enzyme was phenotypically detected by penicillin zone edge test. Among 179 isolates of S. aureus, 116 (64.8%) were MRSA, whereas the remaining 63 (35.2%) isolates were methicillin-sensitive Staphylococcus aureus (MSSA). Staphylococcus aureus infection among ICU and non-ICU patients were found to be 24(13%) and 155(86.6%) respectively. Among 24 ICU patients, 19 had MRSA infection, whereas among 155 non-ICU patients, 97 had MRSA infection. Out of 63 MSSA isolates, only 2 (3.17%) were found to be sensitive to Penicillin by Zone-edge test, 04 isolates showed presence of β-lactamase production, while remaining 57 isolates were resistant to Penicillin. At the same time, several class of antibiotics were found to be ineffective against these MRSA isolates. Cases of methicillin-resistant and b–lactamase producing Staphylococcus aureus infections are on the rise in our hospital settings.

Tamarixetin Attenuated the Virulence of Staphylococcus aureus by Directly Targeting Caseinolytic Protease P

Staphylococcus aureus, especially drug-resistant S. aureus infections, is a worldwide healthcare challenge. There is a growing focus on antivirulence therapy against S. aureus. Caseinolytic protease p (ClpP) is a protein hydrolase essential for pathogenicity in S. aureus. A flavonoid compound, tamarixetin, which was screened in this work, was specifically able to inhibit the hydrolytic activity of ClpP on the fluorescent substrate Suc-LY-AMC with an IC₅₀ of 49.73 μM, without affecting the growth of methicillin-resistant S. aureus strain USA300 and was without obvious cytotoxicity. Further assays found that tamarixetin inhibited the transcription of hla, agr, RNAIII, pvl, PSM-α, and spa genes as well as suppressed the protein expression levels of Hla and PVL. Moreover, tamarixetin was observed to dramatically inhibit the hemolytic activity of hla in S. aureus. Consistent with that of S. aureus USA300-ΔclpP, tamarixetin was shown to increase urease expression. The thermal shift and cellular thermal shift assays showed that tamarixetin markedly changed the thermal stability of ClpP. The dissociation constant (K_D) value of tamarixetin with ClpP was 2.52 × 10^-6 M measured by surface plasmon resonance. The molecular docking and ClpP point mutation results also demonstrated that tamarixetin had a strong interaction with ClpP. In vivo study showed that tamarixetin was effective in protecting mice from S. aureus pneumonia by increasing survival, reducing lung tissue load, and slowing down the infiltration of inflammatory factors. In addition, tamarixetin was able to enhance the antibacterial activity of cefotaxime in combination. In conclusion, tamarixetin was promising as a ClpP inhibitor for S. aureus infections.

7,8-Dihydroxyflavone attenuates the virulence of Staphylococcus aureus by inhibiting alpha-hemolysin

Staphylococcus aureus (S. aureus), a Gram-positive bacteria, is an incurable cause of hospital and community-acquired infections. Inhibition bacterial virulence is a viable strategy against S. aureus infections based on the multiple virulence factors secreted by S. aureus. Alpha-hemolysin (Hla) plays a crucial role in bacteria virulence without affecting bacterial viability. Here, we identified that 7,8-Dihydroxyflavone (7,8-DHF), a natural compound, was able to decrease the expression of and did not affect the in vitro growth of S. aureus USA300 at a concentration of 32 μg/mL. It was verified by western blot and RT-qPCR that the natural compound could inhibit the transcription and translation of Hla. Further mechanism studies revealed that 7,8-DHF has a negative effect on transcriptional regulator agrA and RNAIII, preventing the upregulation of virulence gene. Cytotoxicity assays showed that 7,8-DHF did not produce significant cytotoxicity to A549 cells. Animal experiments showed that the combination of 7,8-DHF and vancomycin had a more significant therapeutic effect on S. aureus infection, reflecting the synergistic effect of 7,8-DHF with antibiotics. In conclusion, 7,8-DHF was able to target Hla to protect host cells from hemolysis while limiting the development of bacterial resistance.

Prevalence of Sarcoidosis-Associated Pulmonary Hypertension: A Systematic Review and Meta-Analysis

Background

Sarcoidosis-associated pulmonary hypertension (SAPH) is associated with poor prognosis, conferring up to a 10-fold increase in mortality in patients with sarcoidosis, but the actual prevalence of SAPH is unknown.

Methods

The PubMed, Embase, and Cochrane Library databases were systematically searched for epidemiological studies reporting the prevalence of SAPH up to July 2021. Two reviewers independently performed the study selection, data extraction, and quality assessment. Studies were pooled using random-effects meta-analysis.

Results

This meta-analysis included 25 high-quality studies from 12 countries, with a pooled sample of 632,368 patients with sarcoidosis. The prevalence of SAPH by transthoracic echocardiography in Europe, the United States and Asia was 18.8% [95% confidence interval (CI): 11.1–26.5%], 13.9% (95% CI: 5.4–22.4%) and 16.2% (95% CI: 7.1–25.4%) separately, and the overall pooled prevalence was 16.4% (95%CI: 12.2–20.5%). By right heart catheterization (RHC), the pooled prevalence of SAPH was 6.4% (95% CI: 3.6–9.1%) in general sarcoidosis population, and subgroup analyses showed that the prevalence of SAPH was 6.7% (95% CI: 2.4–11.0%) in Europe and 8.6% (95% CI: −4.1 to 21.3%) in the United States. Further, the prevalence of pre-capillary PH was 6.5% (95% CI: 2.9–10.2%). For the population with advanced sarcoidosis, the pooled prevalence of SAPH and pre-capillary PH by RHC was as high as 62.3% (95% CI: 46.9–77.6%) and 55.9% (95% CI: 20.1–91.7%), respectively. Finally, the pooled prevalence of SAPH in large databases with documented diagnoses (6.1%, 95% CI: 2.6–9.5%) was similar to that of RHC. Substantial heterogeneity across studies was observed for all analyses (I² > 80%, P < 0.001).

Conclusions

The sarcoidosis population has a relatively low burden of PH, mainly pre-capillary PH. However, as the disease progresses to advanced sarcoidosis, the prevalence of SAPH increases significantly.

Drivers of methicillin-resistant Staphylococcus aureus (MRSA) lineage replacement in China

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen subdivided into lineages termed sequence types (STs). Since the 1950s, successive waves of STs have appeared and replaced previously dominant lineages. One such event has been occurring in China since 2013, with community-associated (CA-MRSA) strains including ST59 largely replacing the previously dominant healthcare-associated (HA-MRSA) ST239. We previously showed that ST59 isolates tend to have a competitive advantage in growth experiments against ST239. However, the underlying genomic and phenotypic drivers of this replacement event are unclear.

METHODS

Here, we investigated the replacement of ST239 using whole-genome sequencing data from 204 ST239 and ST59 isolates collected in Chinese hospitals between 1994 and 2016. We reconstructed the evolutionary history of each ST and considered two non-mutually exclusive hypotheses for ST59 replacing ST239: antimicrobial resistance (AMR) profile and/or ability to colonise and persist in the environment through biofilm formation. We also investigated the differences in cytolytic activity, linked to higher virulence, between STs. We performed an association study using the presence and absence of accessory virulence genes.

RESULTS

ST59 isolates carried fewer AMR genes than ST239 and showed no evidence of evolving towards higher AMR. Biofilm production was marginally higher in ST59 overall, though this effect was not consistent across sub-lineages so is unlikely to be a sole driver of replacement. Consistent with previous observations of higher virulence in CA-MRSA STs, we observed that ST59 isolates exhibit significantly higher cytolytic activity than ST239 isolates, despite carrying on average fewer putative virulence genes. Our association study identified the chemotaxis inhibitory protein (chp) as a strong candidate for involvement in the increased virulence potential of ST59. We experimentally validated the role of chp in increasing the virulence potential of ST59 by creating Δchp knockout mutants, confirming that ST59 can carry chp without a measurable impact on fitness.

CONCLUSIONS

Our results suggest that the ongoing replacement of ST239 by ST59 in China is not associated to higher AMR carriage or biofilm production. However, the increase in ST59 prevalence is concerning since it is linked to a higher potential for virulence, aided by the carriage of the chp gene.

MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens

Introduction

Staphylococcus aureus strains, including methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA), are a main cause of nosocomial infection in the world. The majority of nosocomial S. aureus-infection are traced back to a source of contaminated surfaces including surgery tables. We assessed the efficacy of a mixture of levulinic acid (LA) and sodium dodecyl sulfate (SDS), hereafter called MoWa, to eradicate nosocomial pathogens from contaminated surfaces.

Methods and Results

A dose response study demonstrated that MoWa killed 24 h planktonic cultures of S. aureus strains starting at a concentration of (LA) 8.2/(SDS) 0.3 mM while 24 h preformed biofilms were eradicated with 32/1.3 mM. A time course study further showed that attached MRSA bacteria were eradicated within 4 h of incubation with 65/2 mM MoWa. Staphylococci were killed as confirmed by bacterial counts, and fluorescence micrographs that were stained with the live/dead bacterial assay. We then simulated contamination of hospital surfaces by inoculating bacteria on a surface prone to contamination. Once dried, contaminated surfaces were sprayed with MoWa or mock-treated, and treated contaminated surfaces were swabbed and bacteria counted. While bacteria in the mock-treated samples grew at a density of ~104 cfu/cm2, those treated for ~1 min with MoWa (1.0/0.04 M) had been eradicated below limit of detection. A similar eradication efficacy was obtained when surfaces were contaminated with other nosocomial pathogens, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, or Staphylococcus epidermidis.

Conclusions

MoWa kills planktonic and biofilms made by MRSA and MSSA strains and showed great efficacy to disinfect MRSA-, and MSSA-contaminated, surfaces and surfaces contaminated with other important nosocomial pathogens.

Prevalence and determinants of methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus carrier among staff of a tertiary eye hospital in Saudi Arabia

OBJECTIVES

The objective of this study was to estimate the prevalence and risk factors of methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) carriers among staff of a tertiary eye hospital in Saudi Arabia.

METHODS

This retrospective study was conducted in 2019. Nasal and axillary swabs of health-care staff were used to determine carriers of MRSA. Bacteria were identified by culture and sensitivity tests. These isolates were grouped as antibiotic resistant, sensitive, and others not in the S. aureus group. Demographics and other determinants were associated with carrier status.

RESULTS

We evaluated the carrier status of 430 staff. There were 110 (24.9%; 95% confidence interval [CI]: 21.5, 29.7) S. aureus-positive staff, 21 (11.7%; 95% CI: 11.7, 26.4) of who carried the MRSA strain. Carrier status was significantly higher among physicians (31%) compared to nurses (22.5%) and other staff (5.7%) (P < 0.001). MRSA carrier status was significantly associated with >5 years of employment at the eye hospital (P = 0.02). MRSA was significantly associated with staff who were of Indian nationality (75%) compared to other nationalities (P = 0.04) and those who were at the hospital for <5-year stay compared more than 5 years at the hospital (P = 0.001). All carriers responded to decolonization treatment.

CONCLUSIONS

The high prevalence of MRSA and relatively easy treat MRSA carriers points at the need for universal screening for MRSA carriers among eye health staff.

Antibiotic Resistance Pattern of Staphylococcus Aureus Isolated From Pediatrics With Ocular Infections: A 6-Year Hospital-Based Study in China

Staphylococcus aureus (S. aureus) is an important pathogen of ocular infections in pediatrics. The study aimed to identify the prevalence and resistance pattern of S. aureus, especially methicillin-resistant S. aureus (MRSA), in Chinese children with ocular infections. All patients with S. aureus infections were reviewed at a tertiary children's hospital during 2015-2020, and those with ocular infections were investigated for susceptibility results. Of 1,668 S. aureus strains, there were 177 unique isolates from ocular infection. Among them, 45 (25.4%) were MRSA and 132 (74.6%) were methicillin-sensitive S. aureus (MSSA). The proportion of MRSA did not change over time. Most of the strains were obtained from the neonate ward and ophthalmology department (n = 88, 49.7%, and n = 85, 48.0%, respectively), while eye secretion and pus were the main specimen types (n = 128, 72.3%, and n = 37, 20.9%, respectively). MRSA was significantly resistant against penicillin class (97.8%), erythromycin (71.1%), clindamycin (71.1%), and tetracycline (32.1%), with a high multidrug resistance (MDR) rate of 71.1%. However, MRSA was highly sensitive to levofloxacin. Resistance rates against erythromycin and ciprofloxacin as well as MDR percentage all increased among MSSA in children above 1 year of age, ophthalmology department, and outpatient population and decreased in eye secretion specimen. The mean resistance percentage remained stable for MRSA and MSSA during the study period. The survey of ocular S. aureus pathogens in pediatrics and their antibiotic resistance patterns helps in clinical treatment. MRSA with many strains demonstrating MDR is highly prevalent in children with ocular infections in Southeast China. Levofloxacin is an effective topical antibiotic for ocular MRSA infection, while erythromycin has a high resistance rate. The antibiotic resistance patterns of MRSA and MSSA differs and varies by different stratifications. A cautious use of antibiotics should be considered.

Antimicrobial activity of omadacycline in vitro against bacteria isolated from 2014 to 2017 in China, a multi-center study

BACKGROUND

Omadacycline (ZL-2401) is a semi-synthetic derivative of minocycline. It has a broadspectrum activity against Gram-positive and Gram-negative bacteria, and atypical pathogens. The objective of this study was to evaluate the antibacterial activity of omadacycline against recently collected bacterial isolates from Chinese patients.

RESULTS

Omadacycline showed potent activity against all Gram-positive pathogens: S. aureus MICs were low regardless of susceptibility to methicillin (methicillin-resistant Staphylococcus aureus, MRSA: N = 97, MIC_50/90 0.12/0.25 mg/L, 98.5% susceptible; methicillin-sensitive Staphylococcus aureus, MSSA: N = 100, MIC_50/90 0.12/0.12 mg/L, 100.0% susceptible). Omadacycline was also very effective against β-haemolytic streptococci (MIC_50/90, 0.06/0.12 mg/L), viridans group streptococci (MIC_50/90,<0.03/0. 06 mg/L), and enterococci (MIC_50/90, 0.03/0.12 mg/L). Against S. pneumoniae, omadacycline was highly active regardless of penicillin-resistance (MIC₉₀ 0.06 mg/L) and despite the fact that less than 10.0% of these strains were susceptible to tetracycline. Omadacycline exhibited good in vitro activity against Enterobacterales isolates (MIC_50/90, 2/8 mg/L), inhibiting 81.7% of the isolates at ≤4 mg/L. M. catarrhalis isolates (MIC_50/90, 0.12/0.25 mg/L) were fully susceptible to omadacycline at ≤0.5 mg/L.

CONCLUSIONS

Omadacycline showed potent in vitro activity against most common bacterial pathogens, and even against highly resistant problem pathogens, such as MRSA, penicillin-R and tetracycline-R S. pneumoniae and enterococci. The susceptibility rate of Chinese isolates was similar to those reported in other countries, but the decreased activity against K. pneumoniae isolates in the present study should be noted.

A Systemic Literature Review and Meta-Analysis Reporting the Prevalence and Impact of Methicillin-Resistant Staphylococcus aureus Infection in India

Aim and objective

This systematic review and meta-analysis was conducted to assess the prevalence, burden and epidemiology of methicillin-resistant S. aureus (MRSA). This systemic review was also aimed to highlight the challenges in the diagnosis and management of methicillin-resistant S. aureus (MRSA) in India (for all age groups). We also examined the published literature on the available treatment options and the role of prevention in the management of MRSA in India. By summarizing the currently available data, our objectives were to highlight the need for the prevention of MRSA infections and also emphasize the role of vaccination in the prevention of MRSA infections in India.

Methodology

Electronic databases such as PubMed and databases of the National Institute of Science Communication and Information Resources and Indian Council of Medical Research Embase were searched for relevant literature published from 2005/01/01 to 2020/05/13 in English language, according to the predefined inclusion and exclusion criteria. A manual search was also conducted using the key term "MRSA 'or' Methicillin Resistant Staphylococcus aureus 'and' India." An independent reviewer extracted data from the studies using a structured Microsoft Excel spreadsheet, and a meta-analysis of proportion for MRSA prevalence with a corresponding 95% confidence interval (CI) for all included individual studies were performed.

Result

A total of 34 studies involving 16 237 patients were included in the final meta-analysis. The pooled proportion of patients with MRSA infection was 26.8% (95% CI: 23.2%-30.7%). The MRSA infection was more prevalent among male patients (60.4%; 95% CI: 53.9%-66.5%) as compared to female patients (39.6%; 95% CI: 33.5%-46.1%), while the prevalence of MRSA was higher among adults (18 years and above; 32%; 95% CI: 5%-80%) in comparison to pediatric patients (0-18 years; 68%; 95% CI: 20%-94.8%). The degree of heterogeneity was found to be significant.

Conclusion

The prevalence of MRSA in India was relatively high at 27% with a higher proportion observed among men aged >18 years. The high prevalence of MRSA infections in India necessitates the implementation of surveillance and preventive measures to combat the spread of MRSA in both hospital and community settings.

All d-Lysine Analogues of the Antimicrobial Peptide HPA3NT3-A2 Increased Serum Stability and without Drug Resistance

Novel antibiotic drugs are urgently needed because of the increase in drug-resistant bacteria. The use of antimicrobial peptides has been suggested to replace antibiotics as they have strong antimicrobial activity and can be extracted from living organisms such as insects, marine organisms, and mammals. HPA3NT3-A2 ([Ala^1,8] HPA3NT3) is an antimicrobial peptide that is an analogue of the HP (2–20) peptide derived from Helicobacter pylori ribosomal protein L1. Although this peptide was shown to have strong antimicrobial activity against drug-resistant bacteria, it also showed lower toxicity against sheep red blood cells (RBCs) and HaCaT cells compared to HPA3NT3. The l-Lys residues of HPA3NT3-A2 was substituted with d-Lys residues (HPA3NT3-A2D; [d-Lys^{2,5,6,9,10,15}] HPA3NT3-A2) to prevent the cleavage of peptide bonds by proteolytic enzymes under physiological conditions. This peptide showed an increased half-life and maintained its antimicrobial activity in the serum against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (pathogen). Furthermore, the antimicrobial activity of HPA3NT3-A2D was not significantly affected in the presence of mono- or divalent ions (Na⁺, Mg²⁺, Ca²⁺). Finally, l- or d-HPA3NT3-A2 peptides exhibited the strongest antimicrobial activity against antibiotic-resistant bacteria and failed to induce resistance in Staphylococcus aureus after 12 passages.