Antimicrobial Susceptibility Testing Research Articles

Antimicrobial resistance pattern and species distribution profile of aerobic bacteria causing sterile body fluid infection from a tertiary care hospital

Objectives: Body fluids such as pleural fluid, ascitic fluid, and cerebrospinal fluid are sterile but they can get infected by different microorganisms leading to life-threatening infections. We conducted this study to evaluate the distribution profile of various aerobic bacteria and their antimicrobial resistance pattern isolated from sterile body fluids from the patients attending a tertiary care hospital in North India. Materials and Methods: This hospital-based cross-sectional observational study was conducted in the Department of Microbiology of a tertiary care hospital. A total of 495 sterile body fluid samples were processed for species-level identification of aerobic bacteria by conventional methods following standard laboratory procedures. The antimicrobial susceptibility testing was performed by Kirby–Bauer disc diffusion method according to clinical and laboratory standards institute guidelines 2020. Results: Out of a total of 495 sterile body fluid samples, 48 were found positive on culture for bacterial pathogens. The predominant organisms isolated from sterile body fluids were Acinetobacter species (35%), followed by Klebsiella species (23%), Escherichia coli (13%), Pseudomonas species (12%), Staphylococcus aureus (13%), and Streptococcus species (4%). All of the Gram-negative isolates were 100% sensitive to Colistin followed by amikacin (67.50%) and gentamicin (60%). The Gram-positive isolates were 100% sensitive to vancomycin and linezolid followed by gentamicin (50%). Conclusion: Infections of sterile body fluids can lead to high morbidity and mortality. The knowledge of the bacteriological and antimicrobial resistance profile of bacteria causing sterile body fluid infections is vital in determining appropriate antimicrobial therapy.

Implementation of a Laboratory Information Management System (LIMS) for microbiology in Timor-Leste: challenges, mitigation strategies, and end-user experiences

BackgroundEffective diagnostic capacity is crucial for clinical decision-making, with up to 70% of decisions in high-resource settings based on laboratory test results. However, in low- and middle-income countries (LMIC) access to diagnostic services is often limited due to the absence of Laboratory Information Management Systems (LIMS). LIMS streamline laboratory operations by automating sample handling, analysis, and reporting, leading to improved quality and faster results. Despite these benefits, sustainably implementing LIMS in LMIC is challenging due to high costs, inadequate infrastructure, and limited technical expertise.MethodsThis study evaluated the implementation of a customised microbiology LIMS at the National Health Laboratory (NHL) in Timor-Leste. The LIMS was deployed in November 2020, with an accompanying online results portal introduced in early 2021. The implementation was assessed via a checklist based on key challenges and requirements for LIMS in LMIC, alongside a post-implementation survey of scientists and clinicians.ResultsThe assessment revealed significant improvements in laboratory processes, including enhanced sample throughput, data management, and result reporting. The LIMS reduced transcription errors and standardised reporting of antimicrobial susceptibility testing (AST), improving data quality and accessibility. However, challenges such as unreliable internet connectivity and the need for ongoing funding and technical support persist. The user satisfaction survey, with responses from 19 laboratory scientists and 15 clinicians, revealed positive feedback on workflow improvements and result accessibility, although concerns about internet speed, sustainability, and the need for further training were noted.ConclusionThis study highlights the importance of careful planning, customisation, and stakeholder engagement in LIMS implementation in LMIC. The success in Timor-Leste demonstrates the potential for improved laboratory quality and patient outcomes, but also underscores the need for ongoing investment in infrastructure, technical expertise, and sustainability planning.

Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan

BackgroundNemonoxacin is a new quinolone with an antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA). Certain sequence types (STs) have been emerging in Taiwan, including fluoroquinolone-resistant ST8/USA300. It’s an urgent need to determine nemonoxacin susceptibility against ST8/USA300 and other emerging lineages, if any. Additionally, molecular characterization of nemonoxacin resistance among different lineages has yet to be defined.MethodsNon-duplicated MRSA blood isolates from five hospitals during 2019–2020 were collected and genotyped by pulsed-field gel electrophoresis, and further correlated to their STs. Antimicrobial susceptibility testing for all antibiotics was performing by using Sensititre standard panel, except nemonoxacin by using agar dilution method. Selected isolates with nemonoxacin MICs ≥ 0.5 mg/mL were sequenced for quinolone resistance-determining regions (QRDRs).ResultsOverall, 915 MRSA isolates belonged to four major lineages, ST8 (34.2%), ST59 (23.5%), ST239 (13.9%), and clonal complex 45 (13.7%). Two-thirds of tested isolates were non-susceptible to moxifloxacin, especially ST8/USA300 and ST239. Of them, proportions of nemonoxacin non-susceptibility by a tentative clinical breakpoint (tCBP) of 1 µg/mL among four major lineages appeared to be different (P = 0.06) and highest in ST239 (22.2%), followed by ST8/USA300 (13.5%). Among 89 isolates sequenced, 44.1% of ST8 and all ST239 isolates had ≥ 3 amino acid substitutions (AAS) in gyrA/parC (group A) or 2 AAS in gyrA/parC with additional AAS in gyrB/parE (group B). Compared to other AAS patterns, isolates in group A had the greatest non-susceptible proportions to nemonoxacin (86.9%; overall/pair-wised comparisons, P < 0.05).ConclusionsOur study confirmed ST8/USA300 MRSA has disseminated in Taiwan. Using a tCBP defined by a higher parenteral daily dosage, nemonoxacin retained potency against moxifloxacin non-susceptible isolates. Patterns of AAS in QRDRs among different lineages may contribute to difference of nemonoxacin susceptibility.

Bicarbonate Within: A Hidden Modulator of Antibiotic Susceptibility

Since its standardization, clinical antimicrobial susceptibility testing (AST) has relied upon a standard medium, Mueller-Hinton Broth/Agar (MHB/A), to determine antibiotic resistance. However, this microbiologic medium bears little resemblance to the host milieu, calling into question the physiological relevance of resistance phenotypes it reveals. Recent studies investigating antimicrobial susceptibility in mammalian cell culture media, a more host-mimicking environment, demonstrate that exposure to host factors significantly alters susceptibility profiles. One such factor is bicarbonate, an abundant ion in the mammalian bloodstream/tissues. Importantly, bicarbonate sensitizes methicillin-resistant Staphylococcus aureus (MRSA) to early-generation β-lactams used for the treatment of methicillin-susceptible S. aureus (MSSA). This “NaHCO3-responsive” phenotype is widespread among US MRSA USA300/CC8 bloodstream and skin and soft tissue infection isolates. Translationally, β-lactam therapy has proven effective against NaHCO3-responsive MRSA in both ex vivo simulated endocarditis vegetation (SEV) and in vivo rabbit infective endocarditis (IE) models. Mechanistically, bicarbonate appears to influence mecA expression and PBP2a production/localization, as well as key elements for PBP2a functionality, including the PBP2a chaperone PrsA, components of functional membrane microdomains (FMMs), and wall teichoic acid (WTA) synthesis. The NaHCO3-responsive phenotype highlights the critical role of host factors in shaping antibiotic susceptibility, emphasizing the need to incorporate more physiological conditions into AST protocols.

Streptococcus pyogenes carriage rate, associated factors and antimicrobial susceptibility profiles among urban and rural schoolchildren at Gondar city, Northwest Ethiopia

Streptococcus pyogenes remains one of the top ten causes of mortality from infectious diseases. Children in low-income nations have high carrier rates of Streptococcus pyogenes, which can serve as a source of infections, including simple superficial infections that may lead to invasive and post-streptococcal diseases, particularly among schoolchildren. This study aimed to assess the prevalence of Streptococcus pyogenes, associated factors, and antimicrobial susceptibility profiles among urban and rural public schoolchildren in Gondar City, Northwest Ethiopia. A school-based comparative cross-sectional study was conducted via a multistage sampling technique among elementary schoolchildren from April to June 2022 in Gondar City. Sociodemographic and clinical data were collected via a pretested structured questionnaire. Standard microbiological methods were used to collect and process throat swabs to isolate Streptococcus pyogenes. An antimicrobial susceptibility test was performed via the disk diffusion method. Epi-Info version 7.2.5 was used to enter the data, which were then exported to SPSS version 25 for analysis. Logistic regression analysis was used to determine the strength of associations between variables, and p < 0.05 was considered statistically significant. The overall prevalence of Streptococcus pyogenes in 438 children was 11.2% (n = 49), with 71.43% (35/49) being urban and 28.57% (14/49) being rural. Low-income parents, hospital admission history, and cigarette smoking in the home were found to be substantially linked with Streptococcus pyogenes carriage among students (p < 0.05). All the Streptococcus pyogenes isolates were susceptible (100%) to penicillin and cefotaxime, but 18.8% and 12.25% of the isolates were resistant to amoxicillin and tetracycline, respectively. The prevalence of Streptococcus pyogenes throat carriage among was intermediate. All the isolates were sensitive to penicillin and cefotaxime, but 18.8% and 12.25% of the isolates were resistant to amoxicillin and tetracycline, respectively. Thus, regular screening and surveillance of Streptococcus pyogenes among schoolchildren should be conducted to minimize carriage or infections and maintain the rational use of antimicrobials. Health education about cigarette smoking in the house also needs to be provided to and the community.

Antibiotic Susceptibility Patterns and Virulence Profiles of Classical and Hypervirulent Klebsiella pneumoniae Strains Isolated from Clinical Samples in Khyber Pakhtunkhwa, Pakistan

The emergence of hypervirulent and carbapenem-resistant hypermucoviscous Klebsiella pneumoniae strains presents a significant public health challenge due to their increased virulence and resistance to multiple antibiotics. This study evaluates the antibiotic susceptibility patterns and virulence profiles of classical and hypervirulent K. pneumoniae strains isolated from various clinical samples. A total of 500 clinical samples were collected from patients at the Mardan Medical Complex and Ayub Medical Complex in KPK between July 2022 and June 2024. Among these, 64 K. pneumoniae strains were isolated and subsequently subjected to antimicrobial susceptibility testing (AST) and phenotypic virulence detection. Among the 64 isolates, 21 (32.8%) exhibited hypermucoviscosity, a characteristic associated with increased pathogenicity. Hemagglutination was observed in 35 (54.1%) of the isolates, indicating the presence of surface adhesins that facilitate bacterial adherence to host tissues. A high prevalence of biofilm formation was noted, with 54 (84%) isolates capable of forming biofilms, which are known to protect bacteria from antibiotics and the host immune response. Most isolates (59/64, 92.1%) were resistant against ampicillin, highlighting its limited efficacy against these strains. Conversely, the lowest resistance was observed for tigecycline, with only 15% (10/64) of the isolates showing resistance, indicating its potential utility as a treatment option. The study also found that 38 (59.3%) of the isolates were extended-spectrum beta-lactamase (ESBL) producers, 42 (65.6%) were multidrug-resistant (MDR), 32 (50%) were extensively drug-resistant (XDR), and 13 (20.3%) were resistant to carbapenems. The genetic study revealed biofilm producer and enhancer genes (mrkD, pgaABCD, fimH, treC, wzc, pilQ, and luxS) mainly in the hypervirulent strains. These hypervirulent strains also show a high number of resistance genes. The findings of this study underscore the critical need for the active surveillance of antimicrobial resistance and virulence determinants in K. pneumoniae. The coexistence of high levels of antibiotic resistance and virulence factors in these isolates poses a severe threat to public health, as it can lead to difficult-to-treat infections and increased morbidity and mortality.

Antimicrobial Resistance Genes in Clinical Escherichia coli Strains from Livestock and Poultry in Shandong Province, China During 2015–2020

Antimicrobial resistant (AMR) Escherichia coli (E. coli) isolated from animals may lead to antibiotic treatment failure and economic losses to farmers. The co-existence of antimicrobial resistant genes (ARGs) in the same isolate presents a major challenge for the prevention and control of infection in multidrug-resistant (MDR) Gram-negative organisms. There have been a lot of studies on the antibiotic resistance of E. coli in livestock and poultry, but few of them have focused on clinical pathogens. Objective: The aim of this study was to explore the genetic characteristics, co-occurrence, and correlations between ARGs of E. coli isolated from the pathological tissues of livestock and poultry in Shandong Province, East China during 2015–2020. Methods: A total of 158 E. coli strains were collected and subjected to antimicrobial susceptibility testing and sequencing by whole-genome Next Generation Sequencing (NGS). Results: MDR strains accounted for 46.20% of the 158 E. coli strains with the highest resistant rate of ciprofloxacin (71.52%). In addition, strains with blaNDM-5/mcr-1.1 and mcr-1.1/mcr-3.24 were found in chickens, while three strains with Tet(X4) were found in pigs. In addition, the most common serotypes detected were the O serotype (76/158) and H serotype (36/158). Moreover, seventy-one STs were found and the most common STs were ST10 (6.33%), ST155 (6.33%), and ST101 (5.69%). The genetic environment analysis of the phylogroups revealed that E. coli belonging to phylogroup B1, phylogroup A, and phylogroup C constituted 39.87%, 27.85%, and 15.19%, respectively. Through the correlation analysis, mcr genes were observed to have certain relationships with ARGS such as blaTEM, floR, catA/B, and oqx. Conclusions: This study demonstrates the high prevalence and gene diversity of MDR E. coli isolated from a clinic in Shandong Province, East China. We predicted the transmission risk of animal-borne Tet(X4)-bearing and mcr-harboring E. coli to public health and provided insight into the relationship of co-existence or co-transfer between mcr with ARGS. These relationships present a great challenge for the infection control of MDR Gram-negative organisms.

Resistome and plasmidome genomic features of mcr-1.1-harboring E. coli: a One Health approach.

This study evaluated the phenotypic and genotypic traits of mcr-1.1-harboring Escherichia coli isolates from chickens, pigs, humans, and farm environments. The resistome and the mobile genetic elements associated with the spread of mcr-1.1 in Southern Brazil were also characterized. The 22 mcr-1.1-harboring E. coli isolates from different origins were selected for antimicrobial susceptibility testing and whole genome sequencing for characterization of the resistome, plasmids, and STs. All isolates presented several resistance genes and harbored the mcr-1.1 gene in a highly similar IncX4 plasmid. Furthermore, the mcr-1.1 gene co-occurred with the mcr-3.12 gene in a multidrug-resistant isolate from the farm environment. These findings demonstrate that the mcr-1.1 gene in E. coli isolates from Brazil is spreading mainly by horizontal transfer of the IncX4 plasmid. The co-occurrence of mcr-1.1 and mcr-3.12 highlights pig farming as an important reservoir of colistin resistance.

Isolation and Characterization of Colistin-Resistant Enterobacteriaceae from Foods in Two Italian Regions in the South of Italy

The emergence of colistin-resistant Enterobacteriaceae in food products is a growing concern due to the potential transfer of resistance to human pathogens. This study aimed to assess the prevalence of colistin-resistant Enterobacteriaceae in raw and ready-to-eat food samples collected from two regions of Italy (Apulia and Basilicata) and to evaluate their resistance phenotypes and genetic characteristics. A total of 1000 food samples were screened, with a prevalence of 4.4% of colistin-resistant Enterobacteriaceae. The majority of the isolates belonged to Enterobacter spp. (60%), followed by Moellerella wisconsensis, Atlantibacter hermannii, Klebsiella pneumoniae, and Escherichia coli, among others. Genomic sequencing and antimicrobial susceptibility testing revealed high levels of resistance to β-lactams, with most isolates exhibiting multidrug resistance (MDR). Notably, seven isolates harbored mcr genes (mcr-1, mcr-9, and mcr-10). Additionally, in four of them were predicted the IncHI2 plasmids, known to facilitate the spread of colistin resistance. Furthermore, 56 antimicrobial resistance genes were identified, suggesting the genetic mechanisms underlying resistance to several antibiotic classes. Virulence gene analysis showed that E. coli and other isolates carried genes linked to pathogenicity, increasing the potential risk to public health. This study emphasizes the role of food as a potential reservoir for colistin-resistant bacteria and the importance of monitoring the spread of AMR genes in foodborne pathogens.

Understanding the clinical and molecular epidemiological characteristics of carbapenem-resistant Acinetobacter baumannii infections within intensive care units of three teaching hospitals

BackgroundCarbapenem-resistant Acinetobacter baumannii (CRAB) is recognized as a common clinical conditional pathogen with blaOXA−23 gene-mediated multidrug-resistance that is a significant threat to public health safety. Timely and effective infection control measures are needed to prevent their spread.MethodsWe conducted a retrospective study of CRAB patients at three teaching hospitals from 2019 to 2022. We identified bacterial isolates, collected clinical data, and performed antimicrobial susceptibility testing. Genome characteristics of isolates were investigated by whole genome sequencing. Multilocus sequence typing and phylogenetic trees were used to assess the genetic similarity of isolates. Acquired antimicrobial resistance genes and virulence factors carried in the isolated group genome were analyzed by ResFinder, PubMLST and VFDB. Sequence alignment was used to analyze genetic environment around blaOXA−23. Phylogenetic tree was constructed to analyze the genetic relationship of isolates.ResultsA total of 92 non-repetitive CRAB isolates were collected, with sputum samples accounting for the majority (94.57%, n = 87) of samples. These were distributed into ST2, with ST2 identified to have the highest prevalence of infection, accounting for 99.99% (n = 91) of all isolates. The major resistance genes identified were blaOXA−23, blaOXA−66, blaOXA−51, and blaADC. Also, 92 CRAB strains showed high levels of resistance to common clinical antibiotics, but not minocycline. Meanwhile, most of the isolates carried virulence genes such as various ompA, csuA, csuB, csuC, csuD, abaI, abaR, lpxC, lpxA, and bmfRS. Single nucleotide polymorphism (SNP) analyses further indicated that the bacterial genome was progressively polymorphic with time. We analyzed the environment of the blaOXA−23 gene and found that CRAB accumulated in the context of prominent environmental antibiotic exposure and had longer survival times in the antibiotic environment, resulting in the tendency of bacteria to develop greater antibiotic resistance.ConclusionsWe find that CRAB is prevalent within the ICU and is progressively resistant to antibiotics over time. Enhanced clinical understanding and timely management of CRAB infections will be crucial to minimize or even eliminate the spread of CRAB within the ICU setting.

Silent Carriers: The Hidden Threat of Antibiotic-Resistant Staphylococcus aureus in Retail Seafood Across Poland’s Tri-City Area

Background/objectives: Antibiotic-resistant Staphylococcus aureus poses a significant risk to food safety and public health, particularly through the consumption of contaminated seafood. This study aimed to assess the presence and antibiotic resistance of S. aureus in seafood sold in the Tri-City area of Poland, addressing a knowledge gap regarding the region. Methods: Seafood samples (n = 89) were categorized according to their origin: domestic—Poland (PL), European countries (ECs), and Asian countries (ACs). S. aureus was isolated using ISO 6888-1 methods, and antimicrobial susceptibility testing was conducted against three antibiotics: erythromycin, clindamycin, and gentamicin, following CLSI guidelines. Results: Of the 89 samples, 68.5% were contaminated with S. aureus. The highest resistance rates were found for erythromycin (30.5%), with gentamicin showing the lowest resistance (8.3%).No significant correlation (p &gt; 0.05) was found between resistance patterns and fish origin or processing level. Conclusions: The results of this study highlight the widespread occurrence of Staphylococcus aureus in fish sold in the Tri-City area, with a notable prevalence of antibiotic-resistant strains.

Frequency of urinary tract infections and antimicrobial susceptibility profile among pregnant females.

Objective: To assess the frequency of UTIs in pregnant females. Study Design: Cross-sectional study. Setting: Department of Gynae and Obstetric, Akhter Saeed Trust Hospital, Lahore. Period: September 2023 to February 2024. Methods: The study was conducted on 300 urine samples collected from pregnant females. Firstly, the urine samples were analyzed for routine examination. A urine culture was performed on CLED agar. The antimicrobial susceptibility testing was done by using the modified Kirby-Bauer method. The obtained results were recorded and analyzed by using SPSS 25.0 software. Results: The mean age of pregnant females was 26.7±4.510. Among 300 urine samples, 120 samples showed positive growth on CLED agar. The growth of Escherichia coli (38.33%) was the highest among them followed by Pseudomonas aeruginosa (25.00%), Candida species (20.09%), and Klebsiella species (16.66%). Conclusion: The overall frequency of UTI in pregnant females was high and, in this study, it was reported to be 40.00%.

Antibiogram Profile of Patients Having Urinary Tract Infection Treated with Most Commonly Used Antibiotics

Background: Urinary tract infections (UTIs) are the most common infections in humans, primarily caused by bacteria, with Escherichia coli (E. coli) responsible for 75-90% of cases. The rise in bacterial resistance is largely due to inappropriate antibiotic use, posing significant public health concerns. This study investigated UTI prevalence and antibiotic resistance to inform optimized treatment guidelines. This study aimed to identify the bacterial pathogens causing UTIs and assess their antimicrobial sensitivity and resistance to commonly used antibiotics. Method: A descriptive cross-sectional study was conducted over six months at Khyber Teaching Hospital's Microbiology Department to assess the antibiogram profile of uropathogens from urine cultures. Urine samples were cultured on CLED media, and biochemical tests were used to identify the uropathogens. Antimicrobial susceptibility testing was performed on the isolates using the Kirby-Bauer disk diffusion method on Mueller Hinton Agar (MHA), following CLSI guidelines. A total of 384 patients' urine samples were collected through a convenient technique and processed as per standard guidelines. The collected data was analyzed using SPSS-22 and shown in tables. Results: Escherichia coli was the most common uropathogen, found in 48.17% (n=185) of cases, with a higher prevalence in females at about 48.4% (n=125). Fosfomycin was the most frequently prescribed antibiotic (31.5%) and showed the highest sensitivity (50.2%). Cefotaxime exhibited the highest resistance (38.45%), followed by Amoxicillin-clavulanic acid (34.8%). Conclusion: Escherichia coli remains the dominant pathogen, with Fosfomycin proving generally effective, while resistance to cefotaxime is notable. These reports show the importance of antibiotic use responsibly. By selecting appropriate antibiotics, we can minimize the resistance rate of uropathogens.

UNSAFE SIPS: PREVALENCE OF PATHOGENIC BACTERIAL DIVERSITY IN DRINKING WATER OF KHAIRPUR CITY PAKISTAN

Background: Access to clean drinking water is vital for public health, yet contaminated water remains a leading cause of morbidity and mortality worldwide. In Pakistan, approximately 30% of diseases and 40% of deaths are waterborne, disproportionately affecting children in vulnerable environments such as schools. Poor water quality poses a significant risk to children's health, necessitating studies to assess microbial contamination and antimicrobial resistance in drinking water. Objective: To evaluate the microbial quality of drinking water in government primary schools in Khairpur, Pakistan, by identifying bacterial diversity, prevalence of pathogenic bacteria, and antimicrobial resistance patterns. Methods: A total of 42 water samples were collected from primary schools across six union councils in Khairpur. Total viable counts (TVC) were determined using serial dilution methods, and coliforms were detected using the membrane filtration method in accordance with WHO protocols. Bacterial isolates were identified and subjected to antimicrobial susceptibility testing using the MicroScan WalkAway 96 plus system. Sensitivity profiling was performed to determine resistance patterns, including multidrug-resistant (MDR) and extended-spectrum β-lactamase (ESBL) production. Results: Microbial contamination exceeded acceptable limits in all samples, with TVC ranging from 9,900 to 23,300 CFU/mL. Coliforms were detected in 57% of samples, and Escherichia coli was the most prevalent pathogen, constituting 47% of identified isolates. Among the 28 coliform isolates, 21.4% were identified as MDR, and 10% were ESBL producers. Antibiotics such as tigecycline, meropenem, and imipenem demonstrated the highest efficacy, whereas ampicillin and amoxicillin were the least effective. Conclusion: This study highlights the poor microbial quality of drinking water in Khairpur's primary schools, posing significant health risks to children. Immediate measures, including improved water treatment and regular monitoring, are crucial to mitigating the burden of waterborne diseases.

Molecular and genetic analysis of methicillin-resistant Staphylococcus aureus (MRSA) in a tertiary care hospital in Saudi Arabia.

Methicillin-resistant Staphylococcus aureus (MRSA) continues to pose significant challenges in healthcare settings due to its multi-drug resistance (MDR) and virulence. This retrospective study examines the molecular and resistance profiles of MRSA isolates from a tertiary care hospital in Saudi Arabia, providing valuable insights into regional epidemiology. A total of 190 MRSA strains were analysed to assess antimicrobial susceptibility, genetic diversity, and virulence factors. Antimicrobial susceptibility testing was conducted according to CLSI guidelines, while molecular characterization involved spa typing, SCCmec typing, and DNA microarray analysis to determine clonal complexes (CCs), resistance genes, and virulence determinants. The isolates showed extensive resistance to beta-lactam antibiotics, with 78% classified as MDR. Notably, resistance to fusidic acid and ciprofloxacin was detected in 70% and 55% of isolates, respectively. The most prevalent clonal complexes-CC5, CC6, and CC22-comprised over 60% of the isolates and exhibited diverse spa types. The Panton-Valentine leukocidin (PVL) gene, linked to heightened virulence, was identified in approximately 20% of isolates, particularly within CC5, CC30, and CC80. Enterotoxin genes (sea and seb) and immune evasion genes (sak, chp, and scn) were also commonly detected, reflecting the isolates' capacity to adapt and persist within the hospital environment. These findings underscore the high burden of MDR MRSA with considerable genetic diversity and virulence potential. The study highlights the urgent need for strengthened molecular surveillance and targeted infection control measures to limit MRSA transmission and effectively manage infection risks in healthcare facilities.

Recent advances in centrifugal microfluidics for point-of-care testing.

Point-of-care testing (POCT) holds significant importance in the field of infectious disease prevention and control, as well as personalized precision medicine. The emerging microfluidics, capable of minimal reagent consumption, integration, and a high degree of automation, play a pivotal role in POCT. Centrifugal microfluidics, also termed lab-on-a-disc (LOAD), is a significant subfield of microfluidics that integrates crucial analytical steps onto a single chip, thereby optimizing the process and enabling high-throughput, automated analysis. By utilizing rotational mechanics to precisely control fluid dynamics without external pressure sources, centrifugal microfluidics facilitates swift operations ideal for urgent medical and field settings. This review provides a comprehensive overview of the latest advancements in centrifugal microfluidics for POCT, covering both theoretical principles and practical applications. We begin by introducing the fundamental operational principles, fluidic control mechanisms, and signal output detection methods. Subsequently, we delve into the typical applications of centrifugal microfluidic platforms in immunoassays, nucleic acid testing, antimicrobial susceptibility testing, and other tests. We also discuss the strengths and potential limitations of centrifugal microfluidic platforms, underscoring their transformative impact on traditional conventional procedures and their significant role in diagnostic practices.

Reliability of various Antimicrobial Susceptibility Testing Methods for Piperacillin/tazobactam in challenging Escherichia coli isolates.

Piperacillin/tazobactam antimicrobial susceptibility testing (AST) against Enterobacterales can be challenging. The aim of this study was to assess the reproducibility of various automated (Vitek®2) and non-automated AST methods (broth microdilution (BMD), minimum inhibitory concentration (MIC) test strip, and disk diffusion) for piperacillin/tazobactam in 'challenging' E. coli isolates. We performed 20 repeated AST for seven clinical E. coli isolates: two resistant to piperacillin/ tazobactam but susceptible for amoxicillin/ clavulanic acid, four isolates with various beta-lactamases coding genes (two blaTEM-1, one blaOXA-1, and one with plasmidal blaampC.), and one isolate where VITEK® 2 initially could not produce MIC measurement for piperacillin/ tazobactam (i.e. no results generated). Upon repetition, the same MIC as the mode value (i.e. the most frequent MIC value of each AST method) was found between 21% to 87% (BMD), 46% to 100% (VITEK®2), and 48% to 100 % (gradient test) of the repetitions. The range of percentage essential agreement (EA, i.e. ±1 doubling dilution from this mode value) was 53% to 100% (BMD), 63% to 100% (VITEK®2), and 100% (gradient test). Percentage categorical agreement (CA, same susceptible of resistant category using EUCAST breakpoint v 14.0) ranged from 71% to 100% (BMD), 85% to 92% (VITEK®2), 76% to 100% (gradient test) and 100% (disk diffusion). In conclusion, this study provides insights into the reliability of AST results for piperacillin/ tazobactam in challenging E. coli isolates. While the results indicate that most methods are generally reproducible, certain isolates may present inconsistent MIC results.

Profiling of antimicrobial resistance genes from Staphylococcus pseudintermedius isolated from dogs with pyoderma using whole genome sequencing.

Staphylococcus pseudintermedius is considered as a most common cause of canine pyoderma. Antimicrobial resistance is considered as a global public health concern. The main aim of the study was to evaluate the distribution of Antimicrobial resistance genes in S. pseudintermedius isolates using whole genome sequencing. In the current work, Antimicrobial susceptibility testing and Whole genome sequencing was performed on Five S. pseudintermedius isolates recovered from canine pyoderma cases presented at Veterinary Clinical Complex, Navsari. Bioinformatics analysis of sequencing data was performed to detect Antimicrobial resistance genes, plasmids and mobile genetic elements in S. pseudintermedius isolates. All S. pseudintermedius isolates shows resistance towards amikacin, ampicillin, cefpodoxime, cephalexin, erythromycin and trimethoprim. Higher sensitivity was observed against clindamycin (4/5, 80 %). A total 15 AMR genes, one plasmid (repUS43), two insertion sequences (ISLgar5 and IS256) and one Integrative Conjugative Element (Tn6009) were detected using whole genome sequencing analysis. This study aids us to know about relationship between antimicrobial resistance and presence of AMR genes, plasmids and mobile genetic elements.

Meningococcal C Disease Outbreak Caused by Multidrug-Resistant Neisseria meningitidis, Fiji.

We describe an outbreak of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup C in Fiji. We created surveillance case definitions and collected data by using standard investigation forms. Bacterial identification, antimicrobial susceptibility testing, and PCR were performed in Fiji. Molecular testing was conducted at the Microbiological Diagnostic Unit in Melbourne, Victoria, Australia. During January 2016-December 2018, a total of 96 confirmed or probable IMD cases were reported. Of case-patients, 61.5% (59/96) were male and 38.5% (37) female, 84.4% (81) were indigenous people of Fiji, and 70.8% (68) were children <15 years of age. Annual incidence increased from 1.8/100,000 population in 2016 to 5.2/100,000 population in 2018. Serogroup C multilocus serotype 4821 that is resistant to ciprofloxacin was prevalent (62.1%, 41/66). Public health measures, which included targeted mass vaccination with monovalent meningitis C vaccine, were effective in controlling the outbreak. We observed a rapid decline in meningitis C cases in subsequent years.

Retention and Caries Preventive Effects of Glass Ionomer and Resin Sealants in School-Aged Children: A Comparative Clinical Study

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