Bioremediation of industrial wastewater heavy metals using solo and consortium Enterobacter spp.

Heavy metals are considered the most common pollutants in industrial wastewater areas. Out of thirty bacterial isolates, only 3 isolates sighted the highest metal resistance activity for Zn+2, Fe+2, Pb+2, Co+2, Mn+2, Ni+2, and Cd+2. The biochemical and DNA homology identification with similarities 99.58%, 99.79%, and 99.86% of those isolates was identified and deposited in WDCM, respectively, as Enterobacter kobei OM144907 SCUF0000311, Enterobacter cloacae OM180597 SCUF0000312, and Enterobacter hormaechei OM181067 SCUF0000313. The minimum tolerance activity (MIC) of heavy metal concentrations against E. kobei and E. cloacae was 25, 15, and 15 mmol/l for Ni+2, Fe+2, and Mn+2, respectively, and 10 mmol/l for Zn+2, Pb+2, Co+2, and Cd+2, while against E. hormaechei, it is 15 mmol/l for Ni+2, Fe+2, and Mn+2 and 10 mmol/l for Zn+2, Pb+2, Co+2, and Cd+2. The consortium and solitary application of bacterial isolates towards heavy metal removal at 100%, 200%, and 300% industrial wastewater concentrations were conducted and showed that more than 90% removal of Zn+2, Fe+2, Pb+2, Mn+2, Ni+2, and Cd+2 from a non-concentrated polluted sample (100%) was reported by the three strains. With doubling the polluted sample concentration (200%), the highest removal efficiency for Zn+2, Pb+2, Mn+2, Ni+2, and Cd+2 was reported by E. cloacae as 70. 75, 66, 65, and 57%, respectively. Removal efficiency after increasing the polluted sample concentration to 300% showed that E. cloacae removed above 45% of all tested heavy metals except Pb+2. Ultimately, E. cloacae exposed the highest efficiency with recommendations for heavy metals removal under higher concentrations.

Enterobacter spp.: Update on Taxonomy, Clinical Aspects, and Emerging Antimicrobial Resistance.

The genus Enterobacter is a member of the ESKAPE group, which contains the major resistant bacterial pathogens. First described in 1960, this group member has proven to be more complex as a result of the exponential evolution of phenotypic and genotypic methods. Today, 22 species belong to the Enterobacter genus. These species are described in the environment and have been reported as opportunistic pathogens in plants, animals, and humans. The pathogenicity/virulence of this bacterium remains rather unclear due to the limited amount of work performed to date in this field. In contrast, its resistance against antibacterial agents has been extensively studied. In the face of antibiotic treatment, it is able to manage different mechanisms of resistance via various local and global regulator genes and the modulation of the expression of different proteins, including enzymes (ß-lactamases, etc.) or membrane transporters, such as porins and efflux pumps. During various hospital outbreaks, the Enterobacter aerogenes and E. cloacae complex exhibited a multidrug-resistant phenotype, which has stimulated questions about the role of cascade regulation in the emergence of these well-adapted clones.

Comparative Analysis of Proteomes of a Number of Nosocomial Pathogens by KEGG Modules and KEGG Pathways.

Nosocomial (hospital-acquired) infections remain a serious challenge for health systems. The reason for this lies not only in the local imperfection of medical practices and protocols. The frequency of infection with antibiotic-resistant strains of bacteria is growing every year, both in developed and developing countries. In this work, a pangenome and comparative analysis of 201 genomes of Staphylococcus aureus, Enterobacter spp., Pseudomonas aeruginosa, and Mycoplasma spp. was performed on the basis of high-level functional annotations-KEGG pathways and KEGG modules. The first three organisms are serious nosocomial pathogens, often exhibiting multidrug resistance. Analysis of KEGG modules revealed methicillin resistance in 25% of S. aureus strains and resistance to carbapenems in 21% of Enterobacter spp. strains. P. aeruginosa has a wide range of unique efflux systems. One hundred percent of the analyzed strains have at least two drug resistance systems, and 75% of the strains have seven. Each of the organisms has a characteristic set of metabolic features, whose impact on drug resistance can be considered in future studies. Comparing the genomes of nosocomial pathogens with each other and with Mycoplasma genomes can expand our understanding of the versatility of certain metabolic features and mechanisms of drug resistance.

Genomic Epidemiology of Global Carbapenemase-Producing Enterobacter spp., 2008-2014.

We performed whole-genome sequencing on 170 clinical carbapenemase-producing Enterobacter spp. isolates collected globally during 2008-2014. The most common carbapenemase was VIM, followed by New Delhi metallo-ß-lactamase (NDM), Klebsiella pneumoniae carbapenemase, oxacillin 48, and IMP. The isolates were of predominantly 2 species (E. xiangfangensis and E. hormaechei subsp. steigerwaltii) and 4 global clones (sequence type [ST] 114, ST93, ST90, and ST78) with different clades within ST114 and ST90. Particular genetic structures surrounding carbapenemase genes were circulating locally in various institutions within the same or between different STs in Greece, Guatemala, Italy, Spain, Serbia, and Vietnam. We found a common NDM genetic structure (NDM-GE-U.S.), previously described on pNDM-U.S. from Klebsiella pneumoniae ATCC BAA-214, in 14 different clones obtained from 6 countries spanning 4 continents. Our study highlights the importance of surveillance programs using whole-genome sequencing in providing insight into the molecular epidemiology of carbapenemase-producing Enterobacter spp.

Warning: spread of NDM-1 in two border towns of Iran.

NDM-1 producing gram-negative bacteria can be resistant to every beta-lactam antibiotic, including carbapenem which is one of the last-lines of antibiotic therapy against multi-drug resistant bacteria. This study aimed to detect the metallo-beta-lactamase in the isolated gram-negative bacteria of the Iranian clinical specimens collected from two major cities in Iran. In this cross sectional study 171 Acinetobacter baumannii, 120 Enterobacter spp. and 145 Klebsiella pneumoniae isolated from clinical specimens of two training hospitals in Tabriz and Mashhad were evaluated. Carbapenem resistant screening was performed according to CLSI guide line. The antibiotic susceptibility testing was prepared for carbapenem resistant strains. Then, the metallo-beta- lactamase genes detection was also carried out by PCR assay and confirmed by sequencing. Sixty-eight, 12 and 22 carbapenem resistant Acinetobacter baumannii, Klebsiella pneumoniae and Enterobacter spp. were respectively confirmed, respectively. blaVIM in 9% and blaNDM-1  in 4% of isolated A. baumannii were observed. blaNDM-1 was also detected in 18% and 25% of K. pneumoniae and Enterobacter spp. isolates, respectively. This is the first report of NDM-1 producer A. baumannii and Enterobacter pp. in Iran. NDM-1 producing gram-negative bacteria can be resistant to all beta-lactam antibiotics and cause complicated challenges in health care systems.

Sulfonamide inhibition studies of the ß-carbonic anhydrase from the newly discovered bacterium Enterobacter sp. B13.

The genome of the newly identified bacterium Enterobacter sp. B13 encodes for a ß-class carbonic anhydrases (CAs, EC 4.2.1.1), EspCA. This enzyme was recently cloned, and characterized kinetically by this group (J. Enzyme Inhib. Med. Chem. 2016, 31). Here we report an inhibition study with sulfonamides and sulfamates of this enzyme. The best EspCA inhibitors were some sulfanylated sulfonamides with elongated molecules, metanilamide, 4-aminoalkyl-benzenesulfonamides, acetazolamide, and deacetylated methazolamide (KIs in the range of 58.7-96.5nM). Clinically used agents such as methazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, zonisamide, sulthiame, sulpiride, topiramate and valdecoxib were slightly less effective inhibitors (KIs in the range of 103-138nM). Saccharin, celecoxib, dichlorophenamide and many simple benzenesulfonamides were even less effective as EspCA inhibitors, with KIs in the range of 384-938nM. Identification of effective inhibitors of this bacterial enzyme may lead to pharmacological tools useful for understanding the physiological role(s) of the ß-class CAs in bacterial pathogenicity/virulence.

Effect of Bacterial Extracellular Polymeric Substances from Enterobacter spp. on Rice Growth under Abiotic Stress and Transcriptomic Analysis.

Plant biostimulants have received attention as sustainable alternatives to chemical fertilizers. Extracellular polymeric substances (EPSs), among the compounds secreted by plant growth-promoting rhizobacteria (PGPRs), are assumed to alleviate abiotic stress. This study aims to investigate the effect of purified EPSs on rice under abiotic stress and analyze their mechanisms. A pot experiment was conducted to elucidate the effects of inoculating EPSs purified from PGPRs that increase biofilm production in the presence of sugar on rice growth in heat-stress conditions. Since all EPSs showed improvement in SPAD after the stress, Enterobacter ludwigii, which was not characterized as showing higher PGP bioactivities such as phytohormone production, nitrogen fixation, and phosphorus solubilization, was selected for further analysis. RNA extracted from the embryos of germinating seeds at 24 h post-treatment with EPSs or water was used for transcriptome analysis. The RNA-seq analysis revealed 215 differentially expressed genes (DEGs) identified in rice seeds, including 139 up-regulated and 76 down-regulated genes. A gene ontology (GO) enrichment analysis showed that the enriched GO terms are mainly associated with the ROS scavenging processes, detoxification pathways, and response to oxidative stress. For example, the expression of the gene encoding OsAAO5, which is known to function in detoxifying oxidative stress, was two times increased by EPS treatment. Moreover, EPS application improved SPAD and dry weights of shoot and root by 90%, 14%, and 27%, respectively, under drought stress and increased SPAD by 59% under salt stress. It indicates that bacterial EPSs improved plant growth under abiotic stresses. Based on our results, we consider that EPSs purified from Enterobacter ludwigii can be used to develop biostimulants for rice.

Declining cephalosporin and fluoroquinolone non-susceptibility among bloodstream Enterobacteriaceae from the UK: links to prescribing change?

OBJECTIVES: The UK saw major increases in cephalosporin and quinolone resistance amongst Enterobacteriaceae from 2001 to 2006, with cephalosporin resistance largely reflecting dissemination of CTX-M extended-spectrum ß-lactamases (ESBLs). We review subsequent trends. METHODS: Data were extracted from Public Health England's national database (LabBase), which collects susceptibility results for bloodstream isolates from hospital microbiology laboratories in England, Wales and Northern Ireland, and from the BSAC Bacteraemia Resistance Surveillance System, which centrally tests bloodstream isolates from 25-40 sentinel UK and Irish laboratories. Reference laboratory submissions were also reviewed. RESULTS: LabBase and BSAC data showed that rates of non-susceptibility to cephalosporins and quinolones rose amongst Escherichia coli and Klebsiella spp. until mid-decade (2004-07) before plateauing or falling; similar falls in non-susceptibility began slightly earlier in Enterobacter spp. These reversals in trend occurred whilst the incidence of E. coli bacteraemias was rising, the incidence of Klebsiella bacteraemias was stable and the incidence of Enterobacter bacteraemias was falling; they were not paralleled in EARS-Net data for continental Europe and did not reflect the displacement of single mechanisms. They coincided with large reductions in hospital cephalosporin and quinolone use, owing to concern about Clostridium difficile, with replacement by penicillin/ß-lactamase inhibitor combinations, which have borderline activity against ESBL producers, but consistently lack activity against carbapenemase producers. CONCLUSIONS: Non-susceptibility to cephalosporins and quinolones has declined among bloodstream Enterobacteriaceae in the UK, probably reflecting prescribing shifts. The penicillin/ß-lactamase inhibitor combinations that have largely replaced cephalosporins and quinolones may add to selection for carbapenemase producers.

Phenotypic and genotypic characteristics of beta-lactamase dominant with CARBA, AmpC, and ESBL-producing bacteria in municipal wastewater influent in Helsinki, Finland.

OBJECTIVES: Analysing samples of municipal wastewater influent (before treatment) can help to map the status of antibiotic-resistant bacteria (ARB) at the population level in sewershed communities and may also help in predicting the public health risks of ARB in surface water because of the outfall of wastewater. In this study, we investigated the bacterial isolates carrying beta-lactamase genes in wastewater and compared their genotypic and phenotypic characteristics. METHODS: A total of 399 bacterial isolates grown on CHROMagarESBL (n = 207) and CHROMagarKPC (n = 192) from composite wastewater influent samples (n = 7) from the Viikinmäki wastewater treatment plant (Helsinki) were subcultured, nucleic acid was extracted, and the prevalence of different beta-lactamase genes was screened with multiplex polymerase chain reaction (PCR). All PCR-positive isolates were identified with MALDI-TOF. RESULTS: A total of 32.6% of isolates (130 of 399) were PCR positive for at least one resistance gene, and 13% of these positive isolates out of 130 had at least three resistance genes. Among the 22 detected genes, blaGES group was the most prevalent, at 25.8% (n = 198; many isolates carried multiple genes), followed by blaMOX (13.1%) and blaTEM (10.1%) as most frequently detected. Furthermore, out of 18 different bacterial species/genera detected as carrying beta-lactamase genes, A. hydrophila/caviae (28.5%), Enterobacter spp. (16.9%), and E. coli (14.6%) were the most prevalent. Enterobacter spp., Aeromonas spp., and K. cryocescens potentially carried AmpC genes, and E. coli carried ESBL genes. CONCLUSION: We recorded a huge variety of beta-lactamases (blaAmpC, blaESBL, and blaCARBA) genes in many potential pathogens that probably originated from both enteric and environmental sources.

ACT-107, a novel variant of AmpC ß-lactamase from Enterobacter huaxiensis isolated from Neotropical leaf frog (Phyllomedusa distincta) inhabiting the Brazilian Atlantic Forest.

OBJECTIVES: The aim of this study was to characterise a broad-spectrum cephalosporin-resistant AmpC-positive Enterobacter huaxiensis colonising the skin of a Neotropical frog (Phyllomedusa distincta) inhabiting the Brazilian Atlantic Forest. METHODS: During a genomic surveillance study of antimicrobial resistance, we screened skin samples from P. distincta. Gram-negative bacteria growing on MacConkey agar plates supplemented with 2 µg/mL ceftriaxone were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. A cephalosporin-resistant E. huaxiensis was sequenced using the Illumina NextSeq platform. Genomic data were analysed using bioinformatics tools, whereas AmpC ß-lactamase was characterised in depth by comparative analysis of amino acids, in silico modelling, and analysis of susceptibility to ß-lactam antibiotics and combinations of ß-lactamase inhibitors. RESULTS: Whole-genome sequencing analysis revealed a novel variant of AmpC ß-lactamase belonging to the ACT family, designated ACT-107 by NCBI. This variant contains 12 novel amino acid mutations within the ACT family, 5 in the signal peptide sequence (Ile2, Met14, Tyr16, Gly18 and Thr20), and 7 in the mature protein (Gln22, His43, Cys60, Thr157, Glu225, Ala252 and Asn310). In silico modelling showed that substitutions occurring in the mature chain are localised in the solvent-accessible surface of the protein, where they are not expected to affect the ß-lactamase activity, as observed in the resistance profile. Strikingly, 'not designated' ACT variants from E. huaxiensis were clustered (> 96% identity) with ACT-107. CONCLUSION: Since E. huaxiensis has been isolated from human infection, ACT-107 requires surveillance and the attention of clinicians.

Multicenter Study of Carbapenemase-Producing Enterobacterales in Havana, Cuba, 2016-2021.

Surveillance of carbapenem resistance is particularly important for Enterobacterales, mainly in countries with limited healthcare resources. We conducted a cross-sectional study to detect carbapenem-resistant Enterobacterales at 10 sentinel hospitals in Havana, Cuba for a six year-period (2016-2021) by the National Reference Laboratory for Health Care-Associated Infections in the Pedro Kourí Institute. A total of 152 isolates were collected with phenotypic production of metallo-ß-lactamase. NDM-type carbapenemase was detected in all the 152 isolates, and KPC-type enzyme gene was simultaneously identified in four NDM-positive isolates. The most abundant carbapenemase-producing Enterobacterales (CPE) species was Klebsiella pneumoniae (69.7%), followed by Enterobacter cloacae complex (13.2%), and Escherichia coli (5.9%). Over the study period, among CPE, prevalence of K. pneumoniae was almost constant, while Enterobacter spp. showed slightly increasing tendency. The urinary tract (36.2%) was the most prevalent source of infection with CPE, followed by bloodstream (26.3%) and surgical wound (17.1%), being frequently derived from Intensive Care Units (35.5%) and urology wards (21.7%). This study revealed the present situation of CPE in hospitals in Havana, Cuba, showing the emergence and dissemination of Enterobacterales producing NDM-type carbapenemase, mainly K. pneumoniae.

Isolation and Characterization of Lytic Bacteriophages Targeting Diverse Enterobacter spp. Clinical Isolates.

Background: Enterobacter spp. are opportunistic pathogens that cause nosocomial infections. Bacteriophages could be used to treat antibiotic-resistant Enterobacter infections. Materials and Methods: We used 10 genetically diverse clinical Enterobacter spp. isolates to identify lytic bacteriophages in hospital and municipal wastewater. Comparative genomics was performed on host bacterial isolates and isolated phages. Activity of each phage against all 10 host isolates was determined. We also tested phage activity against paired isolates from two patients who developed ceftazidime-avibactam resistance. Results: Bacteria belonged to three Enterobacter species and Klebsiella aerogenes. We isolated 12 bacteriophages, most of which belonged to the Myoviridae and Autographiviridae families. Most phages were able to lyse multiple bacterial isolates, and many lysed isolates of different species. Ceftazidime-avibactam-resistant isolates were still phage susceptible, and one isolate showed increased susceptibility compared with the parent isolate. Conclusion: The phages we isolated expand the diversity of Enterobacter-targeting phages, and could be useful for treating antibiotic-resistant Enterobacter infections.

Colistin Susceptibility in Companion Animal-Derived Escherichia coli, Klebsiella spp., and Enterobacter spp. in Japan: Frequent Isolation of Colistin-Resistant Enterobacter cloacae Complex.

Transmission of colistin-resistant Enterobacterales from companion animals to humans poses a clinical risk as colistin is a last-line antimicrobial agent for treatment of multidrug-resistant Gram-negative bacteria including Enterobacterales. In this study, we investigated the colistin susceptibility of 285 Enterobacterales (including 140 Escherichia coli, 86 Klebsiella spp., and 59 Enterobacter spp.) isolated from companion animals in Japan. We further characterized colistin-resistant isolates by multilocus sequence typing (MLST), phylogenetic analysis of hsp60 sequences, and population analysis profiling, to evaluate the potential clinical risk of companion animal-derived colistin-resistant Enterobacterales to humans in line with the One Health approach. All E. coli isolates were susceptible to colistin, and only one Klebsiella spp. isolate (1.2%, 1/86 isolates) was colistin resistant. Enterobacter spp. isolates were frequently colistin resistant (20.3%, 12/59 isolates). In colistin-resistant Enterobacter spp., all except one isolate exhibited colistin heteroresistance by population analysis profiling. These colistin-heteroresistant isolates belonged to clusters I, II, IV, VIII, and XII based on hsp60 phylogeny. MLST analysis revealed that 12 colistin-resistant Enterobacter spp. belonged to the Enterobacter cloacae complex; five Enterobacter kobei (four ST591 and one ST1577), three Enterobacter asburiae (one ST562 and two ST1578), two Enterobacter roggenkampii (ST606 and ST1576), and Enterobacter hormaechei (ST1579) and E. cloacae (ST765) (each one strain). Forty-two percent of the colistin-resistant E. cloacae complex isolates (predominantly ST562 and ST591) belonged to lineages with human clinical isolates. Four E. kobei ST591 isolates were resistant to third-generation cephalosporines, aminoglycosides, and fluroquinolones but remained susceptible to carbapenems. In conclusion, our study is the first to our knowledge to report the frequent isolation of the colistin-resistant E. cloacae complex from companion animals. Furthermore, a subset of isolates belonged to human-associated lineages with resistance to multiple classes of antibiotics. These data warrant monitoring carriage of the colistin-resistant E. cloacae complex in companion animals as part of a domestic infection control procedure in line with the One Health approach.

Genomic landscape of blaGES-5- and blaGES-24-harboring Gram-negative bacteria from hospital wastewater: emergence of class 3 integron-associated blaGES-24 genes.

OBJECTIVES: This study aimed to characterize Gram negative bacteria carrying blaGES carbapenemase genes detected in wastewater from a hospital with no history of detection of clinical isolates producing GES carbapenemases. METHODS: Six hospital effluent samples were screened for carbapenemase-producing organisms (CPO) using CHROMagar mSuperCARBA and MacConkey agar with 1 µg/mL imipenem. Polymerase chain reaction (PCR) amplification and sequencing of carbapenemase genes, multilocus sequence typing, antimicrobial susceptibility testing, and whole-genome sequencing were performed. RESULTS: Among 21 CPO isolates, 11 Klebsiella spp. and 5 Enterobacter kobei isolates carried blaGES-24, and 4 E. roggenkampii and 1 Pseudomonas aeruginosa isolates carried blaGES-5. Genomic analysis of 8 representative isolates comprising 6 blaGES-24-positive and 2 blaGES-5-positive revealed that class 3 integrons with complete or defective Tn402-like transposition modules were predominantly associated with two tandem copies of blaGES-24. Furthermore, a total of 5 new class 3 integrons, In3-18 to In3-22, were identified among 5 blaGES-24 and 1 blaGES-5 plasmids. One strain each of K. pneumoniae subsp. pneumoniae and K. quasipneumoniae subsp. similipneumoniae harboring blaGES-24 plasmids also carried a rare blaVEB-1-positive class 1 integron on a non-typeable plasmid, where these blaVEB-1 plasmids had high sequence similarity. Virulence gene profiles differed between Klebsiella spp. and Enterobacter spp.; the former harbored type III fimbriae cluster, salmochelin, and T6SS type i2 gene clusters, while the latter had curli pili operon, aerobactin, T2SS gene clusters, and T6SS type i3 gene clusters. CONCLUSION: Our findings confirmed the linkage of blaGES-24 with rare Tn402-like class 3 integrons and the structural diversity of their gene cassette arrays.

Antimicrobial, Multi-Drug and Colistin Resistance in Enterobacteriaceae in Healthy Pigs in the Greater Accra Region of Ghana, 2022: A Cross-Sectional Study.

There is little published information on antimicrobial resistance (AMR) in animals in Ghana. We determined the prevalence and factors associated with AMR, multi-drug resistance (MDR-resistance to ≥3 antimicrobial classes) and colistin resistance in Enterobacteriaceae in healthy pigs in Accra, Ghana. Rectal swabs obtained from the pigs on 20 farms from January to March 2022, were examined for Escherichia coli, Enterobacter spp. and Klebsiella pneumoniae. AMR was determined using standard microbiological techniques and the mcr-1 gene detected through molecular analysis. Enterobacteriaceae were isolated from 197 of 200 pigs: these comprised 195 E. coli isolates, 38 Enterobacter spp. and 3 K. pneumoniae, either singly or combined. Over 60% of E. coli were resistant to tetracycline, with 27% and 34% being resistant to amoxicillin/clavulanic acid and ampicillin, respectively; 23% of E. coli and 5% of Enterobacter spp. exhibited MDR phenotypes. Phenotypic colistin resistance was found in 8% of E. coli and Enterobacter spp., with the mcr-1 gene detected in half. Our study findings should be incorporated into on-going AMR, MDR and colistin resistance surveillance programs in Ghana. We further advocate for tailored-specific education for pig farmers on animal antimicrobial use and for strengthened regulatory policy on antimicrobial usage and monitoring in the animal production industry.

Evaluation of the effects of Chlorella vulgaris, Nannochloropsis salina, and Enterobacter cloacae on growth, yield and active compound compositions of Moringa oleifera under salinity stress.

Application of Chlorella vulgaris, Nannochloropsis salina and Enterobacter cloacae has been reported to improve the growth of multiple plant species. Moringa oleifera is a medicinal plant found in Saudi Arabia. Its leaves, flowers and fruit have been used as food. Moringa oleifera is rich in rutin and gallic acid and many other bioactive compounds, which collectively contribute to its demonstrated range of pharmacological activities. In Saudi Arabia, the semi-arid and arid weather presents a significant challenge to agriculture. High salinity in cultivated land is a particular threat. We applied Chlorella vulgaris, Nannochloropsis salina, and Enterobacter cloacae at multiple salinities to Moringa oleifera to investigate their effects on the growth, yield, and photosynthetic pigment content. We also examined possible changes in the phytochemical composition. The application of Chlorella vulgaris, Nannochloropsis salina and Enterobacter cloacae enhanced plant growth and yield, while inhibition was observed at high (6000 ppm) salinity. The presence of Chlorella vulgaris and Nannochloropsis salina altered plant growth and yield and rutin and gallic acid content of Moringa oleifera plants grown in saline conditions. Microalgae species were recommended for use as a bio-fertiliser alternative to mainstream synthetic fertilisers.

Emergence and Persistence over Time of Carbapenemase-Producing Enterobacter Isolates in a Spanish University Hospital in Madrid, Spain (2005-2018).

Carbapenemase production is constantly increasing among different Enterobacterales species. We analyzed the microbiological characteristics and population structure of all carbapenemase-producing Enterobacter spp. (CP-Ent) isolates recovered at the Ramón y Cajal Hospital between 2005 and 2018. Overall, 178 CP-Ent isolates (60.7% colonization, 39.3% clinical) were recovered from 165 hospitalized patients (165/176, 93.7%; medical [102/165], surgical [34/165], and intensive care unit [29/165] areas), emergency unit (4/176, 2.3%), and ambulatory patients (7/176, 4.0%). In addition, three CP-Ent were found in environmental sources. Clinical samples were mainly urine (37.1%). The most frequent matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF)-identified species were Enterobacter cloacae (n = 85) and Enterobacter asburiae (n = 49). hsp60 gene sequencing showed a higher species diversity than MALDI-TOF: 70 Enterobacter hormaechei-clusters III, VI, VIII; 69 Enterobacter roggenkampii-IV; 15 Enterobacter kobei-II; 9 E. asburiae-I; 3 Enterobacter ludwigii-V; and 1 E. cloacae subsp. dissolvens-XII. Nine Klebsiella aerogenes were also identified. Overall, a high clonal diversity (Simpson Diversity Index >0.90) was found among CP-Ent-clusters. Environmental isolates were clonally related to clinical ones. Amikacin and tigecycline showed the highest susceptibility (>93%). VIM-1 (n = 133/181, 73.5%) and OXA-48 (n = 34/181, 18.8%) carbapenemases were predominant, followed by KPC-2 (n = 9/181, 5.0%), KPC-3 (n = 2/181, 1.1%), VIM-2 (n = 1/181, 0.6%), and two coproducers (VIM-1+KPC-2 and VIM-1+KPC-3). Extended-spectrum beta-lactamase (ESBL) coproduction (14.4%) emerged in 2012, mainly associated with blaSHV-12 (p < 0.001), E. roggenkampii (p < 0.001), and colonization (p = 0.03). VIM-1- and OXA-48-CP-Ent fecal carriers increased in our hospital, particularly between 2011 and 2018 (p < 0.001). Moreover, KPC and OXA-48 producers emerged in 2010 and 2012, respectively. They superimposed over VIM producers, which were persistently recovered since first detection in 2005. These results depict increased complexity over time of CP-Ent.

Emerging peptide antibiotics with therapeutic potential.

This review covers some of the recent progress in the field of peptide antibiotics with a focus on compounds with novel or established mode of action and with demonstrated efficacy in animal infection models. Novel drug discovery approaches, linear and macrocyclic peptide antibiotics, lipopeptides like the polymyxins as well as peptides addressing targets located in the plasma membrane or in the outer membrane of bacterial cells are discussed.

Antimicrobial Susceptibility and Molecular Characterization of Carbapenemase-Producing Enterobacter spp. Community Isolates in Belgrade, Serbia.

Antimicrobial resistance represents the emerging problem of modern medicine. Despite the fact that Enterobacter spp. is one of the most resistant pathogens, there has been a paucity of data on molecular epidemiology and antimicrobial susceptibility of community isolates in European countries as well as in Serbia. This study was conducted in 2016 and 2017 with the aim to investigate the prevalence of carbapenem-resistant Enterobacter spp. community isolates, molecular determinants of carbapenem resistance, and their genetic relatedness. Seventeen (1.6%) of 1,040 isolates that were positive for carbapenemase screening in accordance with European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations were included in the study. Minimum inhibitory concentrations for selected antimicrobials were determined by broth microdilution and by disk diffusion for chloramphenicol. Multiplex polymerase chain reactions (PCRs) for blaKPC, blaNDM, blaIMP, blaVIM, and blaOXA-48-like carbapenemase genes were performed. Clonality was assessed by enterobacterial repetitive intergenic consensus (ERIC)-PCR analysis. All isolates were multidrug resistant. The most frequent carbapenemase gene found was blaNDM (70.6%), followed by isolates coharboring blaNDM and blaOXA-48-like genes (23.5%) and a single isolate with the blaOXA-48-like gene (5.9%). ERIC-PCR molecular typing showed six different clusters (A-F) with clonal relatedness among isolates from the same institution and association of clusters E and F with the blaNDM carbapenemase gene. Our results indicate the need for Enterobacter spp. surveillance both in the community and hospitals to prevent spreading of multiresistant clones.