Characterization of Antimicrobial Resistance in Serratia spp. and Citrobacter spp. Isolates from Companion Animals in Japan: Nosocomial Dissemination of Extended-Spectrum Cephalosporin-Resistant Citrobacter freundii

Prevalence, Distribution and Antimicrobial Susceptibility of Enterobacteriaceae and Non-Fermenting Gram-Negative Bacilli Isolated From Environmental Samples in a Veterinary Clinical Hospital in Madrid, Spain

Managing infections caused by multidrug-resistant Gram-negative bacilli is a major public health concern, particularly in hospitals where surfaces can act as reservoirs for resistant microorganisms. Identifying these bacteria in hospital environments is crucial for improving healthcare safety. This study aimed to analyse environmental samples from a veterinary hospital to identify prevalent microorganisms and detect antimicrobial resistance patterns. A total of 183 surface samples were collected from 26 areas at the Veterinary Clinical Hospital of Alfonso X el Sabio University in Madrid. The isolated strains were identified, and susceptibility profiles were determined via the disk diffusion method. Clonality analysis was performed using pulsed-field gel electrophoresis. In total, 109 strains were isolated: 76.15% from the Enterobacteriaceae family and 23.85% non-fermenting Gram-negative bacilli. The isolates included Klebsiella, Enterobacter, Escherichia and Pseudomonas species, which could include high-risk clones, given their ability to carry several antimicrobial resistance genes. The equine area had the highest number of isolates (n = 71), accounting for 65% of the total. High resistance indices were observed against at least five of the 16 antibiotics tested, indicating significant multidrug resistance. Clonality analysis suggested potential cross-transmission within the facility. This study sampled hospital surfaces but not personnel or animals, making contamination sources unclear. Without resampling, the effectiveness of cleaning protocols remains uncertain. Results suggest that hospital staff play a key role in bacterial transmission. The lack of specialised preventive measures in veterinary hospitals highlights a need for further research and improvement.

Haematogenous polyostotic osteomyelitis caused by Serratia marcescens in a cat

A 2-year-old female Bengal cat was referred for acute right forelimb lameness one month after ovariectomy. Physical examination revealed multifocal pain on bone palpation and fever. Radiographs showed mixed lytic-proliferative polyostotic diaphyseal osteopathy of multiple bone segments. Histopathologic evaluation of bone biopsies showed severe chronic pyogranulomatous osteomyelitis and multidrug-resistant Serratia marcescens was cultured. Antibiotic therapy with piperacillin-tazobactam was administered for 60 days, based on susceptibility testing. Lameness and bone pain resolved within 15 days, and radiographs after 30 days showed decreased bone lysis. At a 6-month recheck, the cat recovered completely, and only bone remodelling was evident on radiographs. Multifocal bacterial haematogenous osteomyelitis (HO) caused by Serratia marcescens was diagnosed in an adult immunocompetent cat. HO is infrequently reported in dogs and cats with young and immunocompromised patients being most at risk. Prior ovariectomy and anaesthesia may have predisposed the cat to the development of a hospital-associated infection (HAI), as other aetiologies or predisposing causes for osteomyelitis were reasonably excluded. Serratia marcescens is a gram-negative bacterium recently reported as responsible for human and veterinary HAIs, although it has never been stated for HO in small animals. Early recognition and antibiotic therapy led to good outcome in this case.

Prevalence and antimicrobial resistance of Enterobacteriaceae in the north of Kazakhstan

Background

An increasing number of drugs are used each year in the treatment of small pets (cats and dogs), including medicines (cephalosporins and fluoroquinolones) used in human therapy.

Aim

The purpose of this study was to isolate and explore the antibiotic resistance of opportunistic Enterobacteriaceae (Escherichia coli, Klebsiella, Proteus, Ci trobacter, Enterobacter) from cats and dogs, and to isolate resistance genes in the microorganisms.

Methods

In 2021, 808 samples of biological material from small domestic animals were collected in veterinary clinics in Kostanay. From these, 210 microorganisms were isolated and identified.

Results

A large majority of the strains sampled belonged to E. coli-149 (70.9%), Enterobacter-11 (5.2%), Klebsiella-28 (13.3%), Proteus-12 (5.7%) and 10 Citrobacter isolates (4.8%). In all isolates identified, antibiotic resistance/sensitivity was determined by disc-diffusion method to ampicillin, cefoxitin, gentamicin, levomycetin, tetracycline, ciprofloxacin, norfloxacin, ofloxacin, cefoperazone, cefpodoxime, streptomycin, kanamycin, doxycycline, gemifloxacin, nalidixic acid, furazolidone, furadonine, amoxicillin, and enrofloxacin.

Conclusion

The study has demonstrated that the greatest number of Enterobacteriaceae were sensitive to the action of meropenem, which belongs to the group of beta-lactam antibiotics; resistance was demonstrated against tetracycline, doxycycline, ampicillin, amoxicillin, ofloxacin, and cefpodoxime. The most common genes encoding antimicrobial resistance were as follows: BlaTEM and OXA in 41 and 28 isolates, respectively, encoding resistance to beta-lactams; StrA and StrB in 45 and 48 isolates encoding aminoglycosides; and tetA and tetB in 43 and 28 isolates encoding tetracyclines. Obtained data demonstrate that uncontrolled and frequent use of beta-lactam and tetracycline antibacterials, in cats and dogs, results in the spread of genotypic resistance among micro-organisms of the family Enterobacteriaceae.

Genomic analysis of a cAmpC (CMY-41)-producing Citrobacter freundii ST64 isolated from patient

Antibiotic resistance in Citrobacter freundii is a public health concern. This study evaluated the closed genome of a C. freundii isolated from the stool of a hospitalized patient initially related to a Salmonella outbreak. Confirmation of the isolate was determined by whole-genome sequencing. Nanopore sequencing was performed using a MinION with a Flongle flow cell. Assembly using SPAdes and Unicycler yielded a closed genome annotated by National Center for Biotechnology Information Prokaryotic Genome Annotation Pipeline. Genomic analyses employed MLST 2.0, ResFinder4.1, PlasmidFinder2.1, and VFanalyzer. Phylogenetic comparison utilized the Center for Food Safety and Applied Nutrition (CFSAN)-single nucleotide polymorphism pipeline and Genetic Algorithm for Rapid Likelihood Inference. Antimicrobial susceptibility was tested by broth microdilution following Clinical and Laboratory Standards Institute criteria. Multi-locus sequence type in silico analysis assigned the C. freundii as sequence type 64 and the blaCMY-41 gene was detected in resistome investigation. The susceptibility to antibiotics, determined using Sensititre® plates, revealed resistance to aztreonam, colistin, cefoxitin, amoxicillin/clavulanic acid, sulfisoxazole, ampicillin, and streptomycin. The genetic relatedness of the C. freundii CFSAN077772 with publicly available C. freundii genomes revealed a close relationship to a C. freundii SRR1186659, isolated in 2009 from human stool in Tanzania. In addition, C. freundii CFSAN077772 is nested in the same cluster with C. freundii clinical strains isolated in Denmark, Mexico, Myanmar, and Canada, suggesting a successful intercontinental spread.

Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome Caused by Chlamydia abortus: A Case Report

Background

Pneumonia infected by Chlamydia abortus (C. abortus) is rare, especially complicated with severe acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS).

Case Presentation

We presented the clinical details of a 44-year-old male who was diagnosed with C. abortus pneumonia, which rapidly progressed and ultimately led to ARDS, sepsis and MODS. Although he was initially diagnosed with pneumonia upon admission, no pathogenic bacteria were detected in sputum by conventional tests. Empirical intravenous infusion of meropenem and moxifloxacin was administered, but unfortunately, his condition deteriorated rapidly, especially respiratory status. On Day 2 after extracorporeal membrane oxygenation (ECMO) initiation, metagenomic next-generation sequencing (mNGS) was performed on the patient's bronchoalveolar lavage fluid, which indicated an infection with C. abortus. The patient's antimicrobial therapy was adjusted to oral doxycycline (0.1g every 12h), intravenous azithromycin (0.5g every day), and imipenem and cilastatin sodium (1g every 6h). The patient's condition improved clinically and biologically. However, the patient was discharged due to financial reasons and unfortunately passed away eight hours later.

Conclusion

Infections with C. abortus can result in severe ARDS and serious visceral complications which necessitate prompt diagnosis and active intervention by clinicians. The case highlights the significance of mNGS as an essential diagnostic tool for uncommon pathogens. Tetracyclines, macrolides or their combinations are effective choices for treatment of C. abortus pneumonia. Further study is needed to explore the transmission routes of C. abortus pneumonia and establish precise guidelines for antibiotic treatment.

Detection and Antimicrobial Resistance of Enterobacteriaceae other than Escherichia Coli in Raccoons from the Madrid Region of Spain

Introduction

Raccoons are an invasive alien species widely distributed in the Madrid region of Spain. These animals can carry a variety of enteric bacteria with associated antimicrobial resistance, which can infect humans and livestock. However, to our knowledge, the presence of non-E. coli Enterobacteriaceae in raccoons has not been previously studied.

Material and Methods

We conducted a study to examine the species distribution of Enterobacteriaceae isolates other than E. coli, as well as their antimicrobial resistance, in the faeces of 83 raccoons in the Madrid region.

Results

We detected 12 Enterobacteriaceae isolates other than E. coli belonging to seven different species: Citrobacter freundii (1 isolate), Citrobacter gillenii (3 isolates), Citrobacter murliniae (1 isolate), Citrobacter portucalensis (2 isolates), Enterobacter hormaechei subsp. hoffmannii (1 isolate), Hafnia paralvei (2 isolates) and Raoultella ornithinolytica (2 isolates). These isolates were found in 7 of the 83 (8.4%) animals studied. To our knowledge, this study is the first report of the presence of non-E. coli Enterobacteriaceae in raccoon faeces. All isolates but one were resistant to at least one of the 14 antimicrobials tested. Resistance to ampicillin (83.3%), amoxicillinclavulanic acid (50%) and cefoxitin (33.3%) was the most frequent.

Conclusion

Our study indicates that raccoons are a potential source of infection with Enterobacteriaceae other than E. coli for humans and livestock in the Madrid region.

Phylogeographical Landscape of Citrobacter portucalensis Carrying Clinically Relevant Resistomes

During a surveillance study conducted to assess the occurrence and genomic landscape of critical priority pathogens circulating at the human-animal-environment interface in Brazil, as part of the Grand Challenges Explorations-New Approaches to Characterize the Global Burden of Antimicrobial Resistance program, two multidrug-resistant (MDR) Citrobacter portucalensis carrying bla_CTX-M-15 extended-spectrum β-lactamase (ESBL) genes, isolated from green sea turtles, were characterized. Genomic and phylogeographical analysis of C. portucalensis genomes available in public databases revealed the intercontinental dissemination of clades carrying different arrays of clinically relevant genes conferring resistance to carbapenems, broad-spectrum cephalosporins, cephamycins, aminoglycosides and fluoroquinolones, disinfectants, and heavy metals. Our observations suggest that C. portucalensis could be emerging as critical priority bacteria of both public and One Health importance worldwide.

IMPORTANCE The global spread of antibiotic-resistant priority pathogens beyond the hospital setting is a critical issue within a One Health context that integrates the human-animal-environment interfaces. On the other hand, next-generation sequencing technologies along with user-friendly and high-quality bioinformatics tools have improved the identification of bacterial species, and bacterial resistance surveillance. The novel Citrobacter portucalensis species was proposed in 2017 after taxonomic reclassification and definition of the strain A60^T isolated in 2008. Here, we presented genomic data showing the occurrence of multidrug-resistant C. portucalensis isolates carrying bla_CTX-M-15 ESBL genes in South America. Additionally, we observed the intercontinental dissemination of clades harboring a broad resistome to clinically relevant antibiotics. Therefore, these findings highlight that C. portucalensis is a global MDR bacteria that carries intrinsic bla_CMY- and qnrB-type genes and has become a critical priority pathogen due to the acquisition of clinically relevant resistance determinants, such as ESBL and carbapenemase-encoding genes.

Editorial for Special Issue "Multidrug-Resistant Pathogens"

The era of injudicious use of antibiotics in both humans and animals has led to the selection of multidrug-resistant (MDR) pathogens, which in turn has left the medical community with limited therapeutic options [...].

Biosafety considerations and risk reduction strategy for a new veterinary faculty building and teaching hospital in Sweden

Introduction

This paper describes a hazard- and risk-based strategy and recommendations on relevant biosafety levels in facility design of a new veterinary faculty building including a veterinary medical teaching hospital. Both animal and human health were considered.

Materials and methods

Agents listed in the regulatory frameworks on animal and human health were identified as the main potential hazards. Suggestions on biosafety level and facility design were based on the official risk grouping of those agents, the associated risk management procedures, and biosafety experiences from previous faculty buildings.

Results and Discussion

It was suggested that VHC should not be designed for work with agents requiring facilities at biosafety levels 3 and 4, and that actions in cases of accidental exposure to notifiable infections should follow the regulatory requirements. Facilities requiring biosafety level 2 were identified from risk scenarios and transmission routes.

Experiences from the first five years of operation revealed good prevention of spread of infection from patients in isolation facilities and successful elimination of Salmonella and MRSA from the large animal clinic.

Conclusion

In order to avoid costly construction mistakes, an overall biosafety strategy should be formulated and used as guidance for architects and other relevant stakeholders designing facilities for the animal health sector. Regulatory requirements on infectious diseases must be complied with.

Lineage, Antimicrobial Resistance and Virulence of Citrobacter spp

Citrobacter spp. are opportunistic human pathogens which can cause nosocomial infections, sporadic infections and outbreaks. In order to determine the genetic diversity, in vitro virulence properties and antimicrobial resistance profiles of Citrobacter spp., 128 Citrobacter isolates obtained from human diarrheal patients, foods and environment were assessed by multilocus sequence typing (MLST), antimicrobial susceptibility testing and adhesion and cytotoxicity testing to HEp-2 cells. The 128 Citrobacter isolates were typed into 123 sequence types (STs) of which 101 were novel STs, and these STs were divided into five lineages. Lineages I and II contained C. freundii isolates; Lineage III contained all C. braakii isolates, while Lineage IV and V contained C. youngae isolates. Lineages II and V contained more adhesive and cytotoxic isolates than Lineages I, III, and IV. Fifty-one of the 128 isolates were found to be multidrug-resistant (MDR, ≥3) and mainly distributed in Lineages I, II, and III. The prevalence of quinolone resistance varied with Lineage III (C. braakii) having the highest proportion of resistant isolates (52.6%), followed by Lineage I (C. freundii) with 23.7%. Seven qnrB variants, including two new alleles (qnrB93 and qnrB94) were found with Lineage I being the main reservoir. In summary, highly cytotoxic MDR isolates from diarrheal patients may increase the risk of severe disease.