Monitoring Of Antimicrobial Susceptibility Research Articles

Molecular Epidemiology Clinical Manifestations, Decolonization Strategies, and Treatment Options of Methicillin-Resistant Staphylococcus aureus Infection in Neonates

Preterm and low-birth-weight neonates are particularly susceptible to methicillin-resistant Staphylococcus aureus (MRSA) colonization, whereas MRSA infection is associated with significant neonatal morbidity and mortality globally. The objective of our study was to examine the current body of knowledge about molecular traits, epidemiology, risk factors, clinical presentation, decolonization techniques, and available treatments for MRSA infection in neonates. MRSA strains that predominate in neonatal units, namely healthcare-associated (HA)-MRSA, differ from community-acquired (CA)-MRSA strains in molecular characteristics, toxin synthesis, including Panton-Valentine leukocidin, and resistance to antibiotics. Colonization with MRSA predisposes neonates to infection. The clinical impact of MRSA infection includes bacteremia, sepsis, pneumonia, endocarditis, osteomyelitis, septic arthritis, skin and soft tissue infections, and toxic shock syndrome. To reduce MRSA transmission, colonization, and infection, customized approaches are required, including continuous surveillance of MRSA epidemiology, new techniques for detecting MRSA resistance, and the application of basic preventive measures. Antimicrobial susceptibility monitoring is essential to identify the best empirical antimicrobial treatments. The growing antibiotic resistance of MRSA remains challenging, and vancomycin is still the best option. Further extensive research and surveillance are warranted to explore the genetic diversity and prevalence of MRSA.

Dynamic evolution of ceftazidime-avibactam resistance from a single patient through the IncX3_NDM-5 plasmid transfer and blaKPC mutation

The rapid dissemination of carbapenem-resistant Enterobacterales (CRE) especially carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a great threat to global public health. Ceftazidime-avibactam, a novel β-lactam/β-lactamase inhibitor combination, has been widely used due to its excellent antibacterial activity against KPC-producing K. pneumoniae. However, several resistance mechanisms have been reported since its use. Here, we conducted a series of in vitro experiments to reveal and demonstrate the dynamic evolution of ceftazidime-avibactam resistance including interspecies IncX3_NDM-5 plasmid transfer between Enterobacter cloacae and K. pneumoniae and blaKPC mutation from blaKPC-2 to blaKPC-33. Through the analysis of conjugation frequency and fitness cost, the IncX3_NDM-5 plasmid in this study showed strong transmissibility and stability in E. coli EC600 and clinical strain K. pneumoniae 5298 as recipient strain. With increasing ceftazidime-avibactam concentration, the conjugation frequency remained at 10-3-10-5, while the mutation frequency of K. pneumoniae 5298 was 10-6-10-8 at the same concentration. Further plasmid analysis (the IncX3_NDM plasmid from this study and other 658 plasmids from the NCBI database) revealed the diverse origin and genetic structure of blaNDM-5 carrying plasmids. E. coli (42.9%), China (43.9%), IncX3 (66.6%) are the most common strains, regions, and Inc types respectively. By analysing of genetic environment detected in IncX3 plasmids, the dominant structures (168/258, 65.1%) were identified: ISKox3-IS26-blaNDM-5-IS5-ISAba125-Tn3000-Tn3. In additon, several structural variations were found in the core gene structure. In conclusion, the high fitness and transmissibility of the IncX3_NDM-5 plasmids were noteworthy. More importantly, the diverse ceftazidime-avibactam resistance mechanisms including blaNDM-5 tranfer and blaKPC-2 mutation highlighted the importance of the continuous monitoring of antimicrobial susceptibility and carbapenemases subtype during ceftazidime-avibactam treatment.

Antimicrobial Susceptibility of Canine and Feline Urinary Tract Infection Pathogens Isolated from Animals with Clinical Signs in European Veterinary Practices during the Period 2013-2018.

Bacterial urinary tract infections (UTIs) occur frequently in companion animals and are often treated with antibiotics. However, antimicrobial resistance can severely hamper treatment success. Therefore, antimicrobial susceptibility monitoring is key. UTI isolates were obtained from dogs and cats in two collection periods (ComPath II: 2013-2014 and ComPath III: 2017-2018) as part of CEESA's ComPath programme. Susceptibility testing of the UTI isolates (2021 in total) was carried out at one central laboratory using agar and broth dilution methodology as recommended by the Clinical and Laboratory Standards Institute. Escherichia coli was the most frequently isolated bacterium in UTI in both dogs (46.9%, 43.1%) and cats (61.2%, 48.3%) across ComPath II and ComPath III, respectively. The percentage of resistance in E. coli was low (<10%) across both programmes in both dogs and cats except for trimethoprim-sulfamethoxazole (dogs ComPath III: 12.9%; cats ComPath II: 13.0%) and enrofloxacin (10.5%), marbofloxacin (11.4%), and doxycycline (98.8%) for dogs in ComPath III. Three (7.5%) of the 40 isolated S. aureus bacteria in total were MRSA and harboured mecA. The level of multidrug resistance (MDR) was generally low and ranged from 0.0% for feline coagulase-negative Staphylococcus spp. to 11.7% for canine Proteus spp., except for a peak of MDR observed in canine Klebsiella isolates from ComPath II (36.7%). Overall, antimicrobial resistance for most canine and feline UTI pathogens isolated during the ComPath II and ComPath III programmes was low (1-10%) to moderate (10-20%).

Antimicrobial Resistance in Selected Bacteria from Food Animals in New Zealand 2018–2022

Antimicrobial resistance (AMR) presents a significant threat to human health worldwide. One important source of antimicrobial-resistant infections in humans is exposure to animals or animal products. In a phased survey, we investigated AMR in 300 Escherichia coli isolates and 300 enterococci (Enterococcus faecalis and E. faecium) isolates each from the carcasses of poultry, pigs, very young calves, and dairy cattle (food animals); all Salmonella isolates from poultry, very young calves, and dairy cattle; and 300 Campylobacter (Campylobacter jejuni and C. coli) isolates from poultry. The highest resistance levels in E. coli were found for sulfamethoxazole, tetracycline, and streptomycin, for all food animals. Cefotaxime-resistant E. coli were not found and low resistance to ciprofloxacin, colistin, and gentamicin was observed. The majority of enterococci isolates from all food animals were bacitracin-resistant. Erythromycin- and/or tetracycline-resistant enterococci isolates were found in varying proportions from all food animals. Ampicillin- or vancomycin-resistant enterococci isolates were not identified, and ciprofloxacin-resistant E. faecalis were not found. Salmonella isolates were only recovered from very young calves and all eight isolates were susceptible to all tested antimicrobials. Most Campylobacter isolates were susceptible to all tested antimicrobials, although 16.6% of C. jejuni were resistant to quinolones and tetracycline. Results suggest that AMR in E. coli, enterococci, Salmonella, and Campylobacter isolates from food animals in New Zealand is low, and currently, AMR in food animals poses a limited public health risk. Despite the low prevalence of AMR in this survey, ongoing monitoring of antimicrobial susceptibility in bacteria from food animals is recommended, to ensure timely detection of AMR with potential impacts on animal and human health.

Antimicrobial susceptibility profiles and genotyping of Neisseria meningitidis of serogroup C, Italy, 2000-2020.

In Italy the introduction of meningococcal C conjugate vaccine in 2005 has led to a significant reduction of invasive meningococcal disease (IMD) caused by Neisseria meningitidis of serogroup C (MenC). However, this serogroup is still responsible of sporadic cases, clusters and local outbreaks. The study aims to investigate the genotype and antimicrobial susceptibility profile of MenC isolates collected in Italy from 2000 to 2020. Bacterial isolates and biological samples (blood or cerebrospinal fluid) from invasive meningococcal cases are collected and characterized at the National Reference Laboratory for IMD of Istituto Superiore di Sanità. Antimicrobial susceptibility was determined by MIC Test Strip Method and interpreted according to the EUCAST breakpoints guideline. Genotypic characteristics, including multi locus sequence typing (MLST), finetype, and antimicrobial resistance target genes were performed and analyzed using the PubMLST database. Genomic comparison of core genome MLST (cgMLST) of MenC genomes was also carried out. From 2000 to 2020, a total of 665 MenC isolates were investigated for antimicrobial susceptibility and 301 for genotyping. Over two decades, almost all MenC isolates resulted susceptible to antimicrobials with few isolates resulting resistant to ciprofloxacin (N = 2), penicillin G (N = 13), and rifampicin (N = 9), respectively. Molecular typing of MenC obtained from isolates or clinical specimens identified mostly the genotype C:P1.5-1,10-8:F3-6:ST-11(cc11). However, phylogenetic analysis, performed on genomes from MenC isolates, identified two sub lineages, 11.1 and 11.2, among cc11, of which the sub lineage 11.2 was the predominant. Wider application of the genomic analysis and monitoring of antimicrobial susceptibility represent key aspects of IMD surveillance and to monitor the continued evolution of these hyperinvasive strains.

Prevalence of Multidrug Resistant &lt;i&gt;Escherichia coli&lt;/i&gt; among Urinary Tract Infection Patients in Rawalpindi and Islamabad, Pakistan

Background: A common infection known as a urinary tract infection arises when bacteria enter the urethra and infect the urinary system. These germs are usually from the skin or the rectum. Antibiotic resistance is one of the world's most concerning topics due to its severity. This study assessed the trends of antibiotic resistance in E.coli isolates from UTI Individuals. Examining the incidence of uropathogenic E.coli and their multidrug resistance pattern in Islamabad and Rawalpindi. Methods: A 6-month duration-based cross-sectional study was carried out at the microbiology department of Pakistan Institute of Medical Sciences (PIMS) Hospital in Islamabad, Pakistan from July to November 2023. Non-probability sampling, specifically convenient sampling, was used in the study. Collected data was analyzed using SPSS software version 20. Result: The analysis of UTI prevalence by age and gender showed that women (68.3%) were more likely to become infected than males (31.6%), with the incidence of infection being highest in the 31–40 age range. Cefixime resistance was greatest at 95%, followed by ceftriaxone resistance at 88.33% and amoxicillin resistance at 78%. 46.6% of them have more than five medication resistance. Conclusion: The results of the study will help the health department create guidelines for antibiotic prescriptions that will aid medical officers in choosing the appropriate antimicrobial treatment. Education programs that focus on raising knowledge are crucial for preventing E. coli infections and lowering the need for Cefixime and other highly resistant medications. Regular monitoring of antimicrobial susceptibility is necessary.

Microbiological and hematological aspects of canine pyometra and associated risk factors

Microbiological and hematological aspects of canine pyometra and associated risk factors

960. Optimizing the report of antimicrobial resistance in Mexican hospitals: An unfinished business.

Abstract Background One of the aims of antimicrobial stewardship programs (ASP) in hospitals is to make an efficient use of the available infrastructure to enhance surveillance and antimicrobial resistance (AMR) reporting. In this study, we aimed to explore specific AMR reporting mechanisms in ASPs in Mexican hospitals in order to highlight potential areas of improvement. Methods An online survey was applied to a purposive sample of 40 hospitals who performed regular antimicrobial stewardship activities in Mexico. Answers regarding a subset of questions on antimicrobial susceptibility monitoring and reporting practices were provided by ASP professionals. Results A total of 39 hospitals (14 private and 25 public hospitals) in 13 states in Mexico answered the subset of the survey. Thirty-three of those (85%) expressed that their databases allowed periodically monitoring of changes in susceptibility and resistance patterns for specific pathogens. As many as 17 hospitals (44%) reported to two external national academic networks and none reported to international ones. Only 10 reported to the National Hospital Network for Epidemiological Surveillance (RHOVE) in charge of AMR data (29%). Thirty hospitals (77%) declared reporting their AMR consolidated results internally to either the epidemiology department, an ASP leader, or other hospital committee. Twenty percent of the surveyed hospitals issued AMR reports to two entities, an additional 10% of them to 3 entities and 5% more to 4 different entities; reporting to &amp;gt;3 entities was observed only in public hospitals. Two hospitals (5%) declared not submitting AMR reports at all. Conclusion The adoption of reporting commitments without guiding national AMR policies derives into the duplicity of processes (reporting to different networks or entities) requiring additional human and financial resources. It also reflects the unavailability of a functional national reporting system allowing all hospitals to monitor and access the reported information nationally or internationally (GLASS). Optimizing AMR surveillance and reporting in Mexico must incorporate the simplification and standardization of reporting processes into an articulated system in line with the National Strategy against AMR. Disclosures Anahí Dreser, PhD, MSD: Grant/Research Support.

Detection of Drug-Resistant Kluyvera intermedia from Zoacys dhumnades.

Zoacys dhumnades is native to china and has important economic and medicinal value, but the pathogenic microorganisms have been reported rarely. Kluyvera intermedia is usually considered a commensal. In this study, Kluyvera intermedia was first isolated from Zoacys dhumnades identical by the 16SrDNA sequence, phylogenetic tree analysis, and biochemical tests. Cell infection experimental did not find cell morphology change significantly compared to control with pathological organs homogenates from Zoacys dhumnades. Antibiotic susceptibility shown Kluyvera intermedia isolates were sensitive to 12 kinds of antibiotics and resistant to 8 kinds of antibiotics. Resistant antibiotic genes screening display gyrA, qnrB, and sul2 were found in Kluyvera intermedia. This is the first report of Kluyvera intermedia associated fatality with Zoacys dhumnades suggesting the need for continuous monitoring of nonpathogenic bacteria antimicrobial susceptibility from human, domestic animals and wildlife.

Outbreak of drug resistance Escherichia coli phylogenetic F group associated urinary tract infection.

Urinary tract infections are one of the most commonly associated human infectious diseases caused by the bacteria Escherichia coli. Escherichia coli is described as having a large number of virulence genes that enable drug resistance, which is a cause for great concern. Monitoring of antimicrobial susceptibility is critical to determining the scope of the problem and selecting appropriate antimicrobial drugs. The current study aimed to identify the distribution of uropathogenic E. coli (UPEC) based on genetic profiles and to determine resistance patterns among isolates. This study employed biological correlations to study the patterns of antibiotic resistance and the distribution of phylogenetic groups of 118 isolates of E. coli and the relationship between them, which were isolated from three hospitals in Baghdad, Iraq. The results of phylogenetic analysis showed that phylogroup F was the most common group among E. coli isolates (37.3%), followed by phylogroups C (20.3%), B2 (15.3%), E (14.4%), UP (4.2%), A and D (3.4%), and B1 (1.7%). The majority of antibiotic resistance patterns were related to penicillin groups (80.5%) and the least to the sulfonamide groups (67.0%). 51.7%, 42.4%, and 1.7% of isolates were Extensive Drug Resistance (XDR), Multi-Drug Resistance (MDR), and Pan Drug Resistance (PDR), respectively. Antibiotic resistance was most commonly detected in group F (35.6%). Our observations revealed that the dominant phylogroup F had the highest prevalence of multi-drug resistance and extensive drug resistance among E. coli isolates. The newly identified phylogroups C, E, and F account for about 72.0% of the E. coli isolates. Such investigations should be conducted in other localities as well, in order to gain a better understanding of the pattern of antibiotic resistance patterns and the frequency of distinct phylogenetic groups.

Clinical and Genomic Investigation of an International Ceftriaxone- and Azithromycin-Resistant Shigella sonnei Cluster among Men Who Have Sex with Men, Montréal, Canada 2017-2019.

ABSTRACTMultidrug-resistant (MDR) Shigella sonnei have become prevalent among men who have sex with men and have become a global public health concern. From June 2017 to April 2019, 32 men were infected with MDR S. sonnei acquired locally, in Montréal, which was suggestive of an outbreak. Antimicrobial susceptibility testing, whole-genome sequencing (WGS), phylogenetic analysis, antimicrobial resistance and virulence characterization, and association to international clusters were performed. The outbreak strain was ceftriaxone- and azithromycin-resistant due to the acquisition of blaCTX-M-27, and mphA and ermB genes, respectively, with reduced susceptibility to ciprofloxacin due to a single point mutation (gyrA S83L). One out of 27 patients treated with a fluoroquinolone experienced microbiological failure. Epidemiological evidence first supported by a rare unique MDR Shigella sonnei documented only in men in 2017 followed by similar pulsed-field gel electrophoresis profiles was confirmed by WGS. A core genome high-quality single-nucleotide variant (hqSNV)-based phylogeny found a median of 6 hqSNV differences among isolates. Virulence gene content was investigated, but no Shiga toxins were detected. An international cluster of highly related isolates was identified (PDS000019750.208) and belonged to the 3.7.29.1.4.1 S. sonnei genotype (Global III VN2.KH1.Aus). Genomic analysis revealed that this Montréal cluster was connected to other documented outbreaks in Australia, the United States, and the United Kingdom. This study highlights the urgent need for public health measures to focus on the prevention and the early detection of S. sonnei, since global transmission patterns of MDR strains is concerning and few antimicrobial treatment options are available.IMPORTANCE Shigella sonnei, an important foodborne pathogen, recently became a frequent sexually transmitted agent involved in large and persistent outbreaks globally among men who have sex with men. Most strains also harbor several multidrug-resistant (MDR) determinants of particular concern. This study characterizes an outbreak strain at the source of an important MDR cluster identified in Montréal in 2017. Associations were made to many high-profile international outbreaks, and the causative S. sonnei lineage of these clusters was identified, which was not evident in past reports. The worldwide occurrence of this strain is of concern since treatment with antimicrobials like ceftriaxone and azithromycin may not be effective, and rare microbiological failures have been documented in patients treated with ciprofloxacin. Our investigation highlights the threats of Shigella spp. infection and the necessity for antimicrobial susceptibility monitoring in order to mitigate S. sonnei’s impact on public health and to avoid transmission to other at-risk communities.

Monitoring of Antimicrobial Susceptibility of Bacteria Isolated from Poultry Farms from 2014 to 2018.

The current situation of antibiotic resistance of most bacterial pathogens was a threat to the poultry and public health with increasing economic losses. Regarding this problem, monitoring of the circulating microorganisms occurred with the antibiotic resistance profile. A total of 657 different samples from internal organs (liver, heart, lung, and yolk) and paper-lining chick boxes were collected from native chicken farms which were submitted to the Reference Laboratory for Veterinary Quality Control on Poultry Production in the period from 2014 to 2018 for the detection of Salmonella, Escherichia coli (E. coli), and Staphylococcus. The bacterial isolates were tested for their antimicrobial susceptibility by disk diffusion technique. Salmonella was isolated from 128 out of 657 (19.5%), E. coli was isolated from 496 out of 657 (75.5%), and Staphylococcus species was isolated from 497 out of 657 (75.6%). All Salmonella positive samples were examined for antibiotic resistance against 10 different antibiotics, and the highest percentage all over the five years was against penicillin, ampicillin, and tetracycline. All E. coli positive samples were examined for antibiotic resistance against 14 different antibiotics, and the highest percentage all over the five years was with ampicillin, tetracycline, norfloxacin, streptomycin, and danofloxacin. All Staphylococcus positive sample species were examined for antibiotic resistance against 14 different antibiotics, and the highest percentage of resistance all over the five years was shown with tetracycline, streptomycin, ampicillin, and nalidixic acid.

Antimicrobial susceptibility monitoring of Mycoplasma hyopneumoniae isolated from seven European countries during 2015–2016

Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia, a chronic respiratory disease, causing significant economic losses. Results from the 2015-2016 MycoPath pan-European antimicrobial susceptibility monitoring survey of M. hyopneumoniae are presented. In total, 147 M. hyopneumoniae porcine isolates from Belgium, France, Germany, Great Britain, Hungary, Italy, and Spain were tested. One isolate per farm was retained from pigs that had not been recently treated with antimicrobial agents. The minimal inhibitory concentration (MIC) of 13 antimicrobial agents was determined in a central laboratory using a broth microdilution method, with Friis Medium, incubated at 35 ± 1 °C for 5-12 days. M. hyopneumoniae NCTC 10110 was used as Quality Control. MIC50/MIC90 (mg/L) values were: enrofloxacin 0.06/1; marbofloxacin 0.06/2; spiramycin 0.06/0.25; tulathromycin ≤0.001/0.004; gamithromycin 0.06/0.5; tylosin 0.016/0.06; tilmicosin 0.06/0.5; florfenicol 0.5/1; doxycycline 0.25/1; oxytetracycline 0.25/2; lincomycin 0.06/0.25; tiamulin 0.016/0.06 and valnemulin ≤0.001/0.004. Compared with the data from 2010 to 2012 MycoPath study (50 isolates), MIC50/90 results were similar and the majority were within ± two dilution steps, except for the MIC50 of oxytetracycline which is more than two dilution steps higher in the present study. Between-country comparisons show some differences in the MIC values for the fluoroquinolones, tulathromycin and tylosin, but the limited sample size per country precludes performing meaningful country comparisons for several countries. Standardized laboratory methods and interpretive criteria for MIC testing of veterinary mycoplasmas are clearly needed; there are currently no clinical breakpoints available to facilitate data interpretation and correlation of MICs with in vivo efficacy.

Prevalence of extended-spectrum &amp;beta;-lactamase in Pseudomonas aeruginosa in tertiary care centre

an opportunistic nosocomial pathogen, its increasing resistance to broad-spectrum beta-lactams, mediated by extended-spectrum betalactamase enzymes (ESBL), is problem worldwide. The present study was undertaken to determine the prevalence of ESBL-production among the clinical isolates of Pseudomonas aeruginosa. Various clinical specimens received in our laboratory were processed and Pseudomonas aeruginosa was identified as per standard microbiological procedure. All isolates were subjected for ESBL screening test. Potential ESBL producer was then subjected for ESBL Phenotypic confirmatory test –Disc Diffusion method. Antimicrobial susceptibility test was performed by Kirby – Bauer disc diffusion method on all confirmed isolates as per Clinical Laboratory Standard Institute (CLSI 2016) guidelines. A total of 322 non duplicate isolates of Pseudomonas aeruginosa identified during the study period. Of these 26.09% (n = 84) of Pseudomonas aeruginosa isolates were found to be ESBL producers. All ESBL positive isolates showed high resistance to ciprofloxacin 79 (94.05%), Gentamicin 61 (72.62%) and tobramycin 60 (71.43%). Resistance was low to drugs like cefoparazone + salbactum 17 (20.24%) and piperacillin + Tazobactum 14 (16.67%), and Imipenem 15 (17.86%). All the isolates showed 100% sensitive to Polymyxin B.Present study highlights the prevalence and drug resistance of ESBL positive Pseudomonas aeruginosa. Regular antimicrobial susceptibility monitoring is essential for judicial use of antibiotics in order to prevent the spread of drug resistance.

Antimicrobial susceptibility monitoring of canine and feline skin and ear pathogens isolated from European veterinary clinics: results of the ComPath Surveillance programme.

The ComPath project is a pan-European programme dedicated to the monitoring of antimicrobial susceptibility of canine and feline pathogens using standardized methods and centralized minimal inhibitory concentration (MIC) determination. To report antimicrobial susceptibilities of major pathogens isolated from nontreated animals with acute clinical signs of skin, wound or ear infections in 2013-2014. MICs were determined by agar dilution for commonly used drugs and interpreted using Clinical and Laboratory Standards Institute (CLSI) breakpoints, if available. Of 1,676 isolates recovered, the main species isolated from dogs were Staphylococcus pseudintermedius, followed by Streptococcus spp., Pseudomonas aeruginosa and Escherichia coli. In cats, Pasteurella multocida, coagulase-negative staphylococci (CoNS) and Staphylococcusaureus were isolated most frequently. Resistance rates observed for S.pseudintermedius were <26.7% for penicillin, clindamycin and chloramphenicol, and ≤11.5% for ampicillin, amoxicillin/clavulanate, cefalexin, cefovecin, gentamicin and fluoroquinolones. For S.aureus, resistance rates ranged up to 90.9% for β-lactams, and were 19.7% for clindamycin, 27% for fluoroquinolones and 0.0-6.1% for other drugs. The mecA gene was confirmed by PCR in 10.6% of S.pseudintermedius, 11.6% of CoNS and 31.4% of S.aureus isolates. In streptococci/enterococci, resistance to penicillin, ampicillin and chloramphenicol ranged from 0.0% to 11.3%, whereas fluoroquinolone resistance ranged from 0.0% to 8.5%. For E.coli, resistance ranged from 13.8 to 15.9% for fluoroquinolones and from 86.2% to 100.0% for β-lactams. Low rates of resistance (0.0-6.3%) were observed in P.multocida, and for P.aeruginosa resistance to gentamicin was 10.3%. Overall, antimicrobial resistance of cutaneous/otic pathogens isolated from dogs and cats was low (1-10%) to moderate (10-20%). For several pathogens, the paucity of CLSI recommended breakpoints for veterinary use is a bottleneck.

Antimicrobial Susceptibility Pattern of Porcine Respiratory Bacteria in Spain.

The monitoring of antimicrobial susceptibility of pig pathogens is critical to optimize antimicrobial treatments and prevent development of resistance with a one-health approach. The aim of this study was to investigate the antimicrobial susceptibility patterns of swine respiratory pathogens in Spain from 2017 to 2019. Bacterial isolation and identification were carried out following standardized methods from samples coming from sacrificed or recently deceased pigs with acute clinical signs compatible with respiratory tract infections. Minimum inhibitory concentration (MIC) values were determined using the broth microdilution method containing a total of 10 and 7–8 antimicrobials/concentrations respectively, in accordance with the recommendations presented by the Clinical and Laboratory Standards Institute (CLSI). The obtained antimicrobial susceptibility varies between pig respiratory pathogens. Actinobacillus pleuropneumoniae (APP) and Pasteurella multocida (PM) were highly susceptible (≥90%) to ceftiofur, florfenicol and macrolides (tilmicosin, tildipirosin and tulathromycin). However, the antimicrobial susceptibility was intermediate (>60% but <90%) for amoxicillin and enrofloxacin in the case of APP and sulfamethoxazole/trimethropim and tiamulin in the case of PM. Both bacteria showed low (<60%) antimicrobial susceptibility to doxycycline. Finally, Bordetella bronchiseptica was highly susceptible only to tildipirosin and tulathromycin (100%) and its susceptibility for florfenicol was close to 50% and <30% for the rest of the antimicrobial families tested. These results emphasize the need of determining antimicrobial susceptibility in pig respiratory cases in order to optimize the antimicrobial treatment in a case-by-case scenario.

Trends and Impact in Antimicrobial Resistance Among Bacteroides and Parabacteroides Species in 2007-2012 Compared to 2013-2017.

Purpose: The aim of this study was to analyze the susceptibility of Bacteroides and Parabacteroides spp. strains, isolated from patients hospitalized in the clinical hospital in Poland to penicillin, amoxicillin with clavulanic acid, imipenem, clindamycin, and metronidazole. Methods: We analyzed susceptibility of 476 isolates to routinely use for the treatment of anaerobic bacterial infections antibiotics. E test method was used to determining the minimal inhibitory concentration values. To show the trend of drug resistance, we compared data from two periods within the years 2003-2017. Results: Research results indicate that the problem of resistance is mainly related to strains belonging to non-fragilis Bacteroides. In the analyzed periods, there was an increase in the percentage of clindamycin-resistant isolates (35.21% vs. 53.33%), amoxicillin/clavulanic acid (2.83% vs. 8.15%), and imipenem (1.41% vs. 3.7%). In isolates belonging to Parabacteroides distasonis, we observed a constant high (∼50%) percentage of clindamycin-resistant strains. The overwhelming majority of B. fragilis strains were resistant to penicillin (>95%) and about 20% of the isolates were not susceptible to clindamycin. Conclusions: Clindamycin, due to the high and increasing percentage of resistant strains, may not be a good choice in the empirical therapy of infections caused by Bacteroides and P. distasonis. Our study highlighted the importance of a routine or at least periodic monitoring of antimicrobial susceptibility of anaerobic Gram-negative bacilli, providing important information for appropriate therapy. The study shows that infection caused (or suspected of being caused) by Bacteroides and Parabacteroides spp. can be empirically treated with metronidazole or imipenem.

Antimicrobial susceptibility of nine udder pathogens recovered from bovine clinical mastitis milk in Europe 2015–2016: VetPath results

VetPath is an ongoing pan-European antimicrobial susceptibility monitoring programme collecting pathogens from diseased cattle, pigs and poultry not recently treated with antibiotics. Non-duplicate isolates (n = 1244) were obtained from cows with acute clinical mastitis in eight countries during 2015-2016 for centrally antimicrobial susceptibility testing according CLSI standards. Among Escherichia coli (n = 225), resistance was high to ampicillin and tetracycline, moderate to kanamycin and low to amoxicillin/clavulanic acid and cefazolin. The MIC50/90 of danofloxacin, enrofloxacin and marbofloxacin were 0.03 and 0.06 μg/mL. For Klebsiella spp. (n = 70), similar results were noted, except for ampicillin and kanamycin. We detected 3.7 % (11/295) Enterobacteriaceae isolates carrying an ESBL/AmpC gene. Staphylococcus aureus (n = 247) and coagulase-negative staphylococci (CoNS; n = 189) isolates were susceptible to most antimicrobials tested except to penicillin (25.1 and 29.1 % resistance). Two S. aureus and thirteen CoNS isolates harboured mecA gene. Streptococcus uberis isolates (n = 208) were susceptible to β-lactam antibiotics (87.1-94.7 % susceptibility), 23.9 % were resistant to erythromycin and 37.5 % to tetracycline. Resistance to pirlimycin was moderate. For Streptococcus dysgalactiae (n = 132) the latter figures were 10.6 and 43.2 %; pirlimycin resistance was low. MIC values for Streptococcus agalactiae, Trueperella pyogenes and Corynebacterium spp. were generally low. This current VetPath study shows that mastitis pathogens were susceptible to most antimicrobials with exceptions of staphylococci against penicillin and streptococci against erythromycin or tetracycline. For most antimicrobials, the percentage resistance and MIC50/90 values among the major pathogens were comparable to that of the preceeding VetPath surveys. This work highlights the high need to set additional clinical breakpoints for antimicrobials frequently used to treat mastitis.

Current trends in the development of resistance to clinically significant antibiotics in Salmonella (review of literature).

Salmonella is one of the leading bacterial pathogens of acute diarrhea as well as foodborne outbreaks. Salmonellosis can occur as gastroenteritis with the development of complications and generalization of infection, also the extra intestinal diseases that require antibiotic therapy are often registered. Currently, the effectiveness of many antibiotics is reduced due to the development of resistance in Salmonella. National Salmonella surveillance systems monitor Salmonella resistance to «critically important for medicine» antibiotics (extended-spectrum cephalosporins and fluoroquinolones), as well as multidrug resistance. Quinoloneresistant Salmonella is considered as a high-priority resitant pathogen by the World Health Organization. The article describes the current situation on salmonellosis in the world. Foreign and Russian current data about the leading Salmonella serotypes in different regions of the world are presented. The prevalence of clinically significant resistance depending of the Salmonella serotypes in countries with state monitoring systems is shown. The authors described the leading molecular resistance mechanisms (chromosomal and plasmid mediated) and showed their prevalence in different Salmonella serotypes. The article gives the information about Salmonella successful international multidrug resistant clones with specific resistance phenotypes and genotypes. The authors describe the molecular methods for detection of resistance mechanisms, and show the necessity and significance of antimicrobial susceptibility monitoring in the epidemiological Salmonella surveillance.

Antibiotic resistance and clonal relatedness of Helicobacter pylori strains isolated from stomach biopsy specimens in northeast of Iran.

Resistant Helicobacter pylori to commonly used antimicrobial agents are associated with severe upper gastrointestinal disorders. To provide an epidemiological picture of Hpylori and characterize the resistance pattern and genetic variation of clinical isolates, stomach biopsies from patients with functional dyspepsia were evaluated in northeast of Iran. In this study, 80 patients were recruited. Finally, fifty Hpylori strains were isolated from antrum and corpus biopsies by culturing on Columbia agar. All strains were identified by standard laboratory procedures. Susceptibility testing of antibiotics was performed using minimum inhibitory concentration test. Allele-specific primer (ASP)-PCR of 23S rRNA which associated with clarithromycin resistance was done among resistant strains. Moreover, cagA gene and polymorphism in vacA were detected. Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was applied to investigate the genetic variations among all strains. Antibiotic resistance pattern of Hpylori strains was as follows: 68% (34/50) to metronidazole, 50% (25/50) to rifampicin, 30% (15/50) to amoxicillin, 28% (14/50) to levofloxacin, 22% (11/50) to clarithromycin, and 16% (8/50) to tetracycline. Multidrug-resistant strains were observed in 19 strains (38%). ASP-PCR of 23S rRNA showed four strains had A2143G mutation, six strains had A2142G mutation, and one strain had a Wt+A2143G mutation. Amplification of virulence-associated genes revealed that cagA was present in 27 isolates (54%) and vacA in 36 isolates (72%). The most common genotype of Hpylori was vacA s1am2 (40%) followed by vacA s2m2 (14%), vacA s1am1 (12%), vacA s1bm1 (4%), and vacA s1bm2 (2%). DNA fingerprinting pattern indicated a high heterogeneity among isolated strains. An alarming level of resistance to metronidazole and rifampicin and high heterogeneity among Hpylori isolates highlighted the importance of continued monitoring of antimicrobial susceptibility and epidemiological surveillance of this pathogen.