Occurence of ArmA and RmtB Aminoglycoside Resistance 16S rRNA Methylases in Extended-Spectrum β-Lactamases Producing Escherichia coli in Algerian Hospitals

Stray Dogs (Mongrels) Are Potent Reservoir of Drug-Resistant Pathogens: A Study in Peri-Urban Areas of Kolkata, India

This study depicts the drug-resistance and phylogenomic characteristics of 365 Escherichia coli (EC) and 76 Klebsiella pneumoniae (KP) isolated from stray dogs (293) in and around Kolkata, India. Initial screening found 59 isolates, including 48 E. coli and 11 KP multidrug resistant, which included 33 extended-spectrum β-lactamase, 41 AmpC β-lactamase and 18 metallo-β-lactamase producers carrying blaNDM-1 (11) and blaNDM-5 (7) genes. Majority of them had the resistant genes such as blaCTX-M (33), blaTEM (18), blaSHV (4), blaOXA (17), blaFOX (2), blaDHA (2), blaCITM (15), blaCMY-2 (13), blaGES (2) and blaVEB (2), qnrS (15), qnrB (3), aac-6'-Ib-cr (14), tetA (26), tetB (14), sul-1 (25), armA (2) and rmtB (6), in addition to adherence genes such as csgA (33), fimA (27), fliC (13), sdiA (33), rcsA (38), and rpoS (39). They also carried plasmid of diverse replicon types of which IncFIA and FIB were the most frequent. Phylogrouping categorized most of the MDR E. coli in phylogroup A (20), B1 (14), and B2 (6). Enterobacteriaceae repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) showed genetic diversity of multidrug resistant isolates irrespective of their origin, resistance, and virulence types, differentiating the EC in five clades (A-E) and KP in four clades (A-D). As these stray dogs, which had no history or scope of previous antimicrobial therapy, were found to have contracted potential antimicrobial resistance pathogens, the role of environment in spread of such pathogens and further possibility of human infections cannot be ruled out.

Novel Antibacterial Agents SAAP-148 and Halicin Combat Gram-Negative Bacteria Colonizing Catheters

The antibiotic management of catheter-related infections (CRIs) often fails owing to the emergence of antimicrobial-resistant strains and/or biofilm/persister apparitions. Thus, we investigated the efficacy of two novel antimicrobial agents, i.e., the synthetic peptide SAAP-148 and the novel antibiotic halicin, against Gram-negative bacteria (GNB) colonizing catheters. The antibacterial, anti-biofilm, and anti-persister activities of both agents were evaluated against Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae strains. The enrolled strains were isolated from catheters and selected based on their resistance to at least three antibiotic classes and biofilm formation potential. Furthermore, the hemolysis and endotoxin neutralization abilities of these agents were explored. The bactericidal activity of both agents was reduced in urine and plasma as compared to buffered saline. In a dose-dependent manner, SAAP-148 and halicin reduced bacterial counts in 24 h preformed biofilms on silicone elastomer discs and eliminated persisters originating from antibiotic-exposed mature 7-day biofilms, with halicin being less effective than SAAP-148. Importantly, SAAP-148 and halicin acted synergistically on E. coli and K. pneumoniae biofilms but not on A. baumannii biofilms. The peptide, but not halicin, decreased the production of IL-12p40 upon exposure to UV-killed bacteria. This preliminary study showed that SAAP-148 and halicin alone/in combination are promising candidates to fight GNB colonizing catheters.

Comparative Genomic Analysis Reveals the Emergence of ST-231 and ST-395 Klebsiella pneumoniae Strains Associated with the High Transmissibility of blaKPC Plasmids

Conjugative transposons in Gram-negative bacteria have a significant role in the dissemination of antibiotic-resistance-conferring genes between bacteria. This study aims to genomically characterize plasmids and conjugative transposons carrying integrons in clinical isolates of Klebsiella pneumoniae. The genetic composition of conjugative transposons and phenotypic assessment of 50 multidrug-resistant K. pneumoniae isolates from a tertiary-care hospital (SQUH), Muscat, Oman, were investigated. Horizontal transferability was investigated by filter mating conjugation experiments. Whole-genome sequencing (WGS) was performed to determine the sequence type (ST), acquired resistome, and plasmidome of integron-carrying strains. Class 1 integrons were detected in 96% of isolates and, among integron-positive isolates, 18 stains contained variable regions. Horizontal transferability by conjugation confirmed the successful transfer of integrons between cells and WGS confirmed their presence in conjugative plasmids. Dihydrofolate reductase (dfrA14) was the most prevalent (34.8%) gene cassette in class 1 integrons. MLST analysis detected predominantly ST-231 and ST-395. BlaOXA-232 and blaCTX-M-15 were the most frequently detected carbapenemases and beta-lactamases in the sequenced isolates. This study highlighted the high transmissibility of MDR-conferring conjugative plasmids in clinical isolates of K. pneumoniae. Therefore, the wise use of antibiotics and the adherence to effective infection control measures are necessary to limit the further dissemination of multidrug-resistant bacteria.

Extended Spectrum β-Lactamase-Producing Escherichia coli from Poultry and Wild Birds (Sparrow) in Djelfa (Algeria), with Frequent Detection of CTX-M-14 in Sparrow

Antimicrobial resistance is a global threat that is spreading more and more in both human and animal niches. This study investigates the antimicrobial resistance and virulence threats of Escherichia coli isolates recovered from intestinal and fecal samples of 100 chickens, 60 turkeys, and 30 sparrows. Extended spectrum β-lactamase (ESBL) producing E. coli isolates were recovered in 12 of the animals tested, selecting one isolate per positive animal: sparrow (eight isolates, 26.7%), turkey (three isolates, 5%), and chicken (one isolate, 1%). The E. coli isolates were ascribed to B1 and D phylogenetic groups. The bla_CTX-M-14 gene was detected in all ESBL-producing E. coli isolates from sparrow. The bla_CTX-M-15 (two isolates) and bla_CTX-M-14 genes (one isolate) were detected in the isolates of turkey, and the bla_CTX-M-1 gene in one isolate from broiler. Three lineages were revealed among the tested isolates (ST/phylogenetic group/type of ESBL/origin): ST117/D/CTX-M-1/broiler, ST4492 (CC405)/D/CTX-M-15/turkey, and ST602/B1/CTX-M-14/sparrow. All isolates were negative for stx1, sxt2, and eae virulence genes. Our findings provide evidence that the sparrow could be a vector in the dissemination of ESBL-producing E. coli isolates to other environments. This study also reports, to our knowledge, the first detection of bla_CTX-M-14 from sparrow at a global level and in turkey in Algeria.

Escherichia coli Isolates Harboring blaNDM Variants and 16S Methylases Belonging to Clonal Complex 131 in Southern Punjab, Pakistan

The emergence of carbapenem-resistant Escherichia coli (CREC) especially harboring the New Delhi Metallo-β-lactamase (bla_NDM) variants are increasingly being reported from many countries, however, the data from Pakistan is limited. In the present study, 109 CREC isolates were obtained from 4,091 E. coli isolates in five tertiary care hospitals in southern Punjab, Pakistan. The antimicrobial susceptibility profiling and screening for the resistance determinants were performed followed by bla_NDM typing and multilocus sequence typing (MLST) to characterize the CREC strains. Among the carbapenemases, 57 CREC isolates were found to harbor bla_NDM. The bla_NDM-1, bla_NDM-5, bla_NDM-7, and bla_NDM-4 variants were identified in 30 (52.6%), 18 (31.6%), (12.3%), 2 (3.5%) isolates, respectively. The ESBL genes, such as bla_CTX-M and bla_TEM, were also found in different combinations, whereas the 16S methylases that is, rmtB and armA were found in 69 (63.3%) and 55 (50.5%) CREC isolates, respectively. The MLST of bla_NDM carrying E. coli revealed eight different sequence types (STs) with ST131 belonging to 21 isolates being the most prevalent. The clonal complex 131 was the predominant complex corresponding to 47 (82.5%) of bla_NDM-positive strains. Large-scale surveillance studies coupled with active infection control policies are suggested on an urgent basis to avoid an epidemic in the future.

Increasing Trends of Association of 16S rRNA Methylases and Carbapenemases in Enterobacterales Clinical Isolates from Switzerland, 2017–2020

Aminoglycosides (AGs) in combination with β-lactams play an important role in antimicrobial therapy in severe infections. Pan-resistance to clinically relevant AGs increasingly arises from the production of 16S rRNA methylases (RMTases) that are mostly encoded by plasmids in Gram-negative bacteria. The recent emergence and spread of isolates encoding RMTases is worrisome, considering that they often co-produce extended-spectrum β-lactamases (ESBLs) or carbapenemases. Our study aimed to retrospectively analyze and characterize the association of carbapenem- and aminoglycoside-resistant clinical isolates in Switzerland during a 3.5-year period between January 2017 and June 2020. A total of 103 pan-aminoglycoside- and carbapenem-resistant clinical isolates were recovered at the NARA (Swiss National Reference Center for Emerging Antibiotic Resistance) during the 2017–2020 period. Carbapenemase and RMTase determinants were identified by PCR and sequencing. The characterization of plasmids bearing resistance determinants was performed by a mating-out assay followed by PCR-based replicon typing (PBRT). Clonality of the isolates was investigated by multilocus sequence typing (MLST). Over the 991 Enterobacterales collected at the NARA during this period, 103 (10.4%) of them were resistant to both carbapenems and all aminoglycosides. Among these 103 isolates, 35 isolates produced NDM-like carbapenemases, followed by OXA-48-like (n = 23), KPC-like (n = 21), or no carbapenemase (n = 13), OXA-48-like and NDM-like co-production (n = 7), and VIM-like enzymes (n = 4). The RMTases ArmA, RmtB, RmtC, RmtF, RmtG, and RmtB + RmtF were identified among 51.4%, 13.6%, 4.9%, 24.3%, 1%, and 1%, respectively. Plasmid co-localization of the carbapenemase and the RMTase encoding genes was found among ca. 20% of the isolates. A high diversity was identified in terms of the nature of associations between RMTase and carbapenemase-encoding genes, of incompatibility groups of the corresponding plasmids, and of strain genetic backgrounds, highlighting heterogeneous importations rather than clonal dissemination.

Antimicrobial Resistance and Molecular Epidemiology of Uropathogenic Escherichia coli Isolated From Female Patients in Shanghai, China

Urinary tract infection (UTI) is one of the most common bacterial infections and UTI is the most common extraintestinal infectious disease entity in women worldwide. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTI. While antimicrobial resistance has emerged as one of the principal problems of UTI, little is known about the epidemiology of UPEC isolated from female patients in Shanghai. This study aimed to describe the antimicrobial resistance and molecular epidemiology of UPEC isolated from female patients in Shanghai, China. UPEC isolates were collected from female patients from July 2019 to June 2020 in Shanghai and a total of 151 isolates were obtained randomly. Antimicrobial susceptibility testing was performed using the disk diffusion method. Multilocus sequencing type, phylogenetic groups, antimicrobial resistance genes, and virulence genes were detected by polymerase chain reaction. In our study, no carbapenem-resistant isolates were found, but fluoroquinolone-resistant and multi-drug resistant UPEC accounted for 62.25% and 42.38%, respectively. The phylogenetic group B2 (58.94%) predominated, followed by phylogenetic group D (26.49%). The most prevalent sequence type was ST1193 (25.83%), which was first reported in Shanghai. The rate of extended-spectrum β-lactamase (ESBL)-positive isolates was 39.74% and the dominant ESBL genotype was bla_CTX-M-14 (21/60), followed by bla_CTX-M-55 (12/60). Mutations in gyrA were detected in the majority of fluoroquinolone-resistant isolates (90/94), followed by parC (85/94) and parE (71/94). The aac (3) -IIa was also found in 85% of aminoglycoside resistance isolates. Among 151 UPEC isolates, the common virulence genes were csgA (97.35%), fimH (92.72%), sitA (82.12%), and malX (65.56%). In conclusion, the high antimicrobial resistance of UPEC isolated from female patients, harboring a series of virulence genes, are troublesome for medical practitioners in Shanghai. At present, the prevalent ST1193 and emerging bla_CTX-M-55 make UTI therapy more challenging.

Genetic basis of molecular mechanisms in β-lactam resistant gram-negative bacteria

Antibiotic-resistant bacteria are considered one of the major global threats to human and animal health. The most harmful among the resistant bacteria are β-lactamase producing Gram-negative species (β-lactamases). β-lactamases constitute a paradigm shift in the evolution of antibiotic resistance. Therefore, it is imperative to present a comprehensive review of the mechanisms responsible for developing antimicrobial resistance. Resistance due to β-lactamases develops through a variety of mechanisms, and the number of resistant genes are involved that can be transferred between bacteria, mostly via plasmids. Over time, these new molecular-based resistance mechanisms have been progressively disclosed. The present review article provides information on the recent findings regarding the molecular mechanisms of resistance to β-lactams in Gram-negative bacteria, including CTX-M-type ESBLs with methylase activity, plasmids harbouring phages with β-lactam resistance genes, the co-presence of β-lactam resistant genes of unique combinations and the presence of β-lactam and non-β-lactam antibiotic-resistant genes in the same bacteria. Keeping in view, the molecular level resistance development, multifactorial and coordinated measures may be taken to counter the challenge of rapidly increasing β-lactam resistance.

Genomic characterization of 16S rRNA methyltransferase-producing Escherichia coli isolates from the Parisian area, France

BACKGROUND

The resistance to all aminoglycosides (AGs) conferred by 16S rRNA methyltransferase enzymes (16S-RMTases) is a major public health concern.

OBJECTIVES

To characterize the resistance genotype, its genetic environment and plasmid support, and the phylogenetic relatedness of 16S-RMTase-producing Escherichia coli from France.

METHODS

We screened 137 E. coli isolates resistant to all clinically relevant AGs from nine Parisian hospitals for 16S-RMTases. WGS was performed on clinical isolates with high-level AG resistance (MIC ≥256 mg/L) and their transformants.

RESULTS

Thirty of the 137 AG-resistant E. coli produced 16S-RMTases: 11 ArmA, 18 RmtB and 1 RmtC. The 16S-RMTase producers were also resistant to third-generation cephalosporins (90% due to a blaCTX-M gene), co-trimoxazole, fluoroquinolones and carbapenems (blaNDM and blaVIM genes) in 97%, 83%, 70% and 10% of cases, respectively. Phylogenomic diversity was high in ArmA producers, with 10 different STs, but a similar genetic environment, with the Tn1548 transposon carried by a plasmid closely related to pCTX-M-3 in 6/11 isolates. Conversely, RmtB producers belonged to 12 STs, the most frequent being ST405 and ST complex (STc) 10 (four and four isolates, respectively). The rmtB gene was carried by IncF plasmids in 10 isolates and was found in different genetic environments. The rmtC gene was carried by the pNDM-US plasmid.

CONCLUSIONS

ArmA and RmtB are the predominant 16S-RMTases in France, but their spread follows two different patterns: (i) dissemination of a conserved genetic support carrying armA in E. coli with high levels of genomic diversity; and (ii) various genetic environments surrounding rmtB in clonally related E. coli.

A prospective surveillance study to determine the prevalence of 16S rRNA methyltransferase-producing Gram-negative bacteria in the UK

OBJECTIVES

To determine the prevalence of 16S rRNA methyltransferase- (16S RMTase-) producing Gram-negative bacteria in patients in the UK and to identify potential risk factors for their acquisition.

METHODS

A 6 month prospective surveillance study was conducted from 1 May to 31 October 2016, wherein 14 hospital laboratories submitted Acinetobacter baumannii, Enterobacterales and Pseudomonas aeruginosa isolates that displayed high-level amikacin resistance according to their testing methods, e.g. no zone of inhibition with amikacin discs. Isolates were linked to patient travel history, medical care abroad, and previous antibiotic exposure using a surveillance questionnaire. In the reference laboratory, isolates confirmed to grow on Mueller-Hinton agar supplemented with 256 mg/L amikacin were screened by PCR for 16S RMTase genes armA, rmtA-rmtH and npmA, and carbapenemase genes (blaKPC, blaNDM, blaOXA-48-like and blaVIM). STs and total antibiotic resistance gene complement were determined via WGS. Prevalence was determined using denominators for each bacterial species provided by participating hospital laboratories.

RESULTS

Eighty-four isolates (44.7%), among 188 submitted isolates, exhibited high-level amikacin resistance (MIC >256 mg/L), and 79 (94.0%) of these harboured 16S RMTase genes. armA (54.4%, 43/79) was the most common, followed by rmtB (17.7%, 14/79), rmtF (13.9%, 11/79), rmtC (12.7%, 10/79) and armA + rmtF (1.3%, 1/79). The overall period prevalence of 16S RMTase-producing Gram-negative bacteria was 0.1% (79/71 063). Potential risk factors identified through multivariate statistical analysis included being male and polymyxin use.

CONCLUSIONS

The UK prevalence of 16S RMTase-producing Gram-negative bacteria is low, but continued surveillance is needed to monitor their spread and inform intervention strategies.

Molecular survey of aminoglycoside-resistant Acinetobacter baumannii isolated from tertiary hospitals in Qazvin, Iran

Aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methylases (16S RMTase) are two main resistance mechanisms against aminoglycosides. This study aimed to evaluate the frequency of AMEs and 16S rRNA methylase genes among aminoglycoside non-susceptible Acinetobacter baumannii isolates and to assess their clonal relationship using repetitive extragenic palindromic-PCR (rep-PCR). In this cross-sectional study, a total of 192 A. baumannii isolates were collected from the patients hospitalized in Qazvin, Iran (January 2016 to January 2018). Identification of isolates was performed by standard laboratory methods and API 20E strips. Antimicrobial susceptibility was determined by Kirby–Bauer method followed by examination of the genes encoding the AMEs and 16S RMTase by PCR and sequencing methods. The clonal relationship of isolates was carried out by rep-PCR. In total, 98.4% of isolates were non-susceptible to aminoglycosides, 98.4%, 97.9% and 83.9% of isolates were found to be non-susceptible against gentamicin, tobramycin and amikacin, respectively. The frequencies of aph(3′)-VI, aac(6′)-Ib, aac(3)-II, aph(3′)-Ia and armA genes were 59.3%, 39.2%, 39.2%, 31.7% and 69.8%, respectively, either alone or in combination. Rep-PCR results showed that the aminoglycoside non-susceptible isolates belonged to three distinct clones: A (79.4%), B (17.5%) and C (3.2%). The findings of this study showed a high frequency for AMEs with the emergence of armA genes among the aminoglycoside non-susceptible A. baumannii isolates. Rational administration of aminoglycosides as well as using an appropriate infection control policy may reduce the presence of resistance to antibiotics in medical centres.

•

Little is known regarding carbapenem resistance mechanisms in A. baumannii in our region.

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More than 85% of our isolates were non-susceptible to carbapenems in Qazvin hospitals, Iran.

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bla_OXA-23, bla_OXA-24, bla_IMP-1, and bla_VIM-1 genes is established in carbapenem resistant A. baumannii isolates.

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Clonal distribution of carbapenem resistant A. baumannii was demonstrated in investigated hospital settings.

Acinetobacter baumannii Sequence Types Harboring Genes Encoding Aminoglycoside Modifying Enzymes and 16SrRNA Methylase; a Multicenter Study from Pakistan

Introduction

The aminoglycosides are widely used for the therapeutic management of infections caused by gram-negative bacteria, including the Acinetobacter baumannii strains. However, the resistance to the members of the aminoglycoside family, such as amikacin, gentamicin, and tobramycin, is increasingly being common among the clinical isolates.

Purpose

This study aimed to investigate the presence of 16SrRNA methylases and aminoglycoside modifying enzymes (AMEs) genes among aminoglycoside resistant A. baumannii isolates and to study the genetic diversity of the clinical population of A. baumannii in local hospitals.

Material and Methods

The 143 A. baumannii clinical strains were analyzed for antimicrobial susceptibility, genetic screening for enzymes conferring aminoglycosides resistance followed by the multilocus sequence typing.

Results

The 133/143 (93%) isolates were non-susceptible to at least one of the tested aminoglycosides, including amikacin, gentamicin, and tobramycin. The MIC distribution has shown that 87.486.7% strains were resistant to amikacin and gentamicin, respectively. The aphA6, aadB, aacC1, and aphA1 were found in 74.1%, 59.4%, 16.1%, and 11.2% isolates, respectively, whereas the armA was found in 28% of the strains having a higher MIC value (MIC; ≥256µg/mL). The MLST data have shown that the ST589 and ST2 were the most common STs and corresponded to 51 (35.7%) and 38 (26.6%) isolates, respectively, and few of the isolates corresponding to these STs were found to harbor the armA gene with a variable genotypic profile for AMEs.

Discussion

The study has reported the incidence of various enzymes conferring aminoglycoside resistance among the A. baumannii clones for the first time from Pakistan. The findings suggest the possibility of transmission of aminoglycoside resistance determinants through the lateral gene transfer as well as clonal dissemination.

Co occurrence of two 16S rRNA methyltrasferases along with NDM and OXA 48 like carbapenamases on a single plasmid in Klebsiella pneumoniae

Abstract:

BACKGROUND:

The carbapenemase-encoding genes, bla_NDM- and bla_OXA-48-like, confer resistance to all the known beta-lactams and are encountered along with other beta-lactamase-encoding genes and/or 16S ribosomal RNA (rRNA)-methylating genes. The co-occurrence of bla_NDM and bla_OXA-48-like on a single plasmid is a rare occurrence.

AIM AND OBJECTIVE:

The purpose of the study was to characterize the plasmids in Klebsiella pneumoniae isolates producing 16S rRNA methyltransferase along with bla_NDM, bla_OXA-48-like, and other resistance encoding genes.

MATERIALS AND METHODS:

One-hundred and seventeen K. pneumoniae clinical isolates which were resistant to aminoglycosides were collected. Polymerase chain reaction-based screening for 16S rRNA methyltransferase genes armA, rmtB, and rmtC; carbapenamase genes bla_NDM, bla_OXA-48-like, bla_IMP, bla_VIM, and bla_KPC; and other resistance genes such as bla_TEM, bla_SHV, bla_CTX-M, and qnr (A, B, and S) determinants acc (6’) Ib-cr was performed. Conjugation experiment was carried out for seven isolates that anchored bla_NDM and bla_OXA-48-like along with any one of the 16S rRNA methyltransferases. The plasmid-based replicon typing for different plasmid-incompatible (Inc) group was performed on the conjugatively transferable plasmids.

RESULTS:

Among the 16S rRNA methyltransferases, armA was more predominant. bla_NDM and bla_OXA-48-like were present in 56 (47.86%) and 22 (18.80%) isolates, respectively. Out of seven isolates which were conjugatively transferable, only four had bla_NDM and bla_OXA-48-like on the same plasmid and they belonged to Inc N and A/C replicon. Three isolates co-harbored 16S rRNA methyltransferases armA, rmtB, and rmtC, and out of the them, one isolate harbored two 16S rRNA methyltransferases armA and rmtB, on the single-plasmid replicon A/C.

CONCLUSION:

This is the first report revealing the coexistence of bla_NDM and bla_OXA-48-like co-harboring two 16S rRNA methylases on a single conjugative plasmid replicon belonging to incompatibility group A/C.

Prevalence of fosfomycin resistance among ESBL-producing Escherichia coli isolates in the community, Switzerland

Our aim was to evaluate the prevalence of fosfomycin-resistant strains among ESBL-producing Escherichia coli isolates recovered from community patients in Switzerland. A total of 1225 ESBL-producing E. coli isolates were collected between 2012 and 2013 from a private and community laboratory. Fosfomycin resistance was assessed by using the novel rapid fosfomycin/E. coli NP test and agar dilution method. Resistant isolates were further investigated for acquired resistance genes fosA1-7 by PCR and sequencing. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to evaluate the clonal relationship among fosA3-carrying isolates. Out of the 1225 ESBL-producing E. coli isolates analyzed in this study, 1208 were fosfomycin susceptible while 17 were fosfomycin resistant. No discrepancy was observed between the rapid fosfomycin/E. coli NP test and the agar dilution method taken as the gold standard. Five out of the 17 resistant isolates carried a fosA-like gene. No clonal relationship was observed among those isolates. Here, the prevalence of fosfomycin resistance among ESBL-producing E. coli isolates in the community is reported for the first time in Switzerland, being ca. 1.4%. Among the five isolates carrying a fosA gene, four encoded the FosA3 enzyme, being the most prevalent fosfomycin-resistant determinant. An excellent correlation was observed between minimum inhibitory concentration-based susceptibility categorization and results of the rapid fosfomycin/E. coli NP test, further indicating the excellent sensitivity and specificity of this recently developed rapid test whose results are obtained in less than 2 h.

High Rate of Association of 16S rRNA Methylases and Carbapenemases in Enterobacteriaceae Recovered from Hospitalized Children in Angola

Acquired 16S rRNA methylases (RMTases) conferring pan-drug resistance to aminoglycosides were searched among enterobacterial isolates recovered in Angola. A total of 36 hospitalized children were screened for rectal colonization using the Superaminoglycoside selective medium. Twenty-two pan-aminoglycoside-resistant enterobacterial isolates were recovered, all of which produced RMTases, i.e., RmtB, ArmA, and RmtC. Highly diverse genetic backgrounds were identified for Escherichia coli and Klebsiella pneumoniae isolates, most of which coproduced carbapenemases NDM-1 or NDM-5, respectively.

Extended-spectrum β-lactamase-producing Escherichia coli in wastewaters and refugee camp in Lebanon

AIM

To evaluate the effects of population influx of refugees on the prevalence of extended-spectrum β-lactamase-producing Escherichia coli in wastewater networks in Lebanon.

MATERIALS & METHODS

Pulsed-field gel electrophoresis, multilocus sequence typing and antibiotic resistance genes typing were performed.

RESULTS

53.1% of isolates recovered from Al-Qaa refugee camp were positive for the tested resistant determinants compared with 49.1% from river effluents. All isolates carried aac(6)-1b and/or aac(3)-II; none carried armA, rmtB, ant(4')-Iia, aph(3')-Ia or carbapenemases. CTX-M-15, TEM-1, OXA-1, CMY-2 and SHV-12 were detected. Single and/or double substitutions were detected in GyrA and ParC. Phylogenetic group B2 and ST6470 were the most prevalent. Pulsed-field gel electrophoresis revealed 19 XbaI patterns and 17 pulsotypes.

CONCLUSION

The introduction of novel resistance patterns into the wastewater network requires effective control.

Emergence of Salmonella enterica serovar Indiana and California isolates with concurrent resistance to cefotaxime, amikacin and ciprofloxacin from chickens in China

The aim of this study was to investigate the prevalence and characterization of Salmonella concerning the poultry industry in China. A total of 170 non-duplicate Salmonella isolates were recovered from the 1540 chicken samples. Among the Salmonella isolates from chickens, the predominant serovars were S. enterica serovar Enteritidis (S. Enteritidis) (49/170, 28.8%), S. enterica serovar Indiana (S. Indiana) (37/170, 21.8%) and S. enterica serovar California (S. California) (34/170, 20.0%). High antimicrobial resistance was observed for ciprofloxacin (68.2%), amikacin (48.2%) and cefotaxime (44.7%). Of particular concerns were the 18 S. Indiana and 17 S. California isolates, which were concurrently resistant to cefotaxime, amikacin and ciprofloxacin. The bla_CTX-M genes, 16S rRNA methylase genes (armA, rmtD or rmtC) and five plasmid-mediated quinolone resistance (PMQR) determinants (aac(6')-Ib-cr, oqxAB, qnrB, qepA and qnrD) were identified in 18 S. Indiana and 17 S. California isolates. To clarify their genetic correlation, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were further conducted. PFGE profiles showed that the majority of S. Indiana and S. California isolates were clonally unrelated with a standard cut-off of 85%. The results of MLST demonstrated that ST17 and ST40 were the most common ST types in S. Indiana and S. California isolates, respectively. Our findings indicated that the multiple antibiotic resistant S. Indiana and S. California isolates were widespread in chicken in China and might pose a potential threat to public health.