Plasmid-mediated fosfomycin resistance in Escherichia coli isolated from pig.

Previous studies have reported plasmid-mediated fosA3 among Escherichia coli originating from human and companion animals. In this study, the plasmid, designated pHK23a originating from a multidrug-resistant E. coli isolate recovered from a slaughter pig in December 2008 in Hong Kong, China was sequenced. In conjugation, the plasmid readily transferred to E. coli J53 at high frequencies. It belongs to the narrow host range IncFII incompatibility group and is 73,607bp in length. Sequence alignment showed that pHK23a has a 59.1kb backbone which shares high homology with the prototype R100 plasmid and a 14.5kb variable region. The variable region includes three genes mediating antimicrobial resistance (fosA3, ΔblaTEM-1, blaCTX-M-3), ten mobile genetic elements (four copies of IS26, insA, ΔinsB, ΔTn2, IS1, ΔISEcp1, Δintl1), the tir transfer inhibition protein, the pemI/pemK addiction system and eight ORFs of unknown functions (orf1, orf2, Δorf3, orf20, orf23, orf24, ycdA and ycdB). The three resistance genes were organized in a novel IS26-composite transposon-like structure. In conclusion, this is the first report of fosA3 containing plasmid in an isolate of pig origin. Since IncFII plasmids spread efficiently in Enterobacteriaceae, the detection of fosA3 with blaCTX-M is worrisome and might become a public health concern. © 2012 Elsevier B.V..postprin

Increase in the nasopharyngeal carriage of non-vaccine serogroup 15 Streptococcus pneumoniae after introduction of children pneumococcal conjugate vaccination in Hong Kong

This study assessed pneumococcal carriage in the early periods after routine use of 13-valent pneumococcal conjugate vaccine (PCV13) in Hong Kong. Nasopharyngeal swabs were obtained from 1110 children (<5 years) admitted with acute illness during September 2010–August 2013. Pneumococcal carriage rate was 13.5% in unvaccinated children, 14.1% in children who had ≥1 PCV dose and 15.3% in children who had ≥3 PCV doses. Nonv-PCV13 serotypes comprised 56.4% of all isolates. The most common serogroup/types were 15 (15A, 5.1%; 15B, 10.3%; 15C, 9.6%; 15F, 0.6%), 19F (17.9%), 6A (7.1%) and 6C (7.1%). Carriage of serogroup 15 was more common among vaccinated children (4.1% versus 0.6%, P = 0.033). Molecular typing revealed that expansion of several clones (clonal complex, CC63, CC199, CC1262, CC3397) was responsible for the increase in serogroup 15. Almost all CC63 and CC3397 isolates were nonsusceptible to both penicillin and erythromycin. The finding highlights the emergence of serogroup 15 following PCV13 use.postprin

Emergence of macrolide-resistant Mycoplasma pneumoniae in Hong Kong is linked to increasing macrolide resistance in the multilocus variable-number tandem-repeat analysis type 4-5-7-2

Macrolide-resistant Mycoplasma pneumoniae (MRMP) is rapidly emerging in Asia, but information on the temporal relationship between the increase in macrolide resistance and changes in strain types is scarce. Between 2011 and 2014, M. pneumoniae infection was diagnosed by PCR as part of routine care in a health care region in Hong Kong. Testing was initiated by clinicians, mainly in patients with suspected M. pneumoniae pneumonia. Specimens positive for M. pneumoniae were retrospectively investigated by macrolide resistance genotyping and a four-locus (Mpn13 to-16) multilocus variable-number tandem-repeat analysis (MLVA) scheme. The overall percentage of M. pneumoniae-positive specimens was 17.9%, with annual rates ranging from 9.8% to 27.2%. The prevalence of MRMP had rapidly increased from 13.6% in 2011 to 30.7% in 2012, 36.6% in 2013, and 47.1% in 2014 (P=0.038). Two major MLVA types, 4-5-7-2 and 3-5-6-2, accounted for 75% to 85% of the infections each year. MLVA types 4-5-7-2 and 3-5-6-2 predominated among macrolide-resistant and macrolide-sensitive groups, respectively. The increase in MRMP was mainly caused by increasing macrolide resistance in the prevalent MLVA type 4-5-7-2, changing from 25.0% in 2011 to 59.1% in 2012, to 89.7% in 2013, and to 100% in 2014 (P<0.001). In conclusion, increasing MRMP in Hong Kong was linked to a single MLVA type, which was both prevalent and increasingly resistant to macrolides. Copyright © 2015, American Society for Microbiology. All Rights Reserved.postprin

High prevalence of Escherichia coli sequence type 131 among antimicrobial-resistant E. coli isolates from geriatric patients

Previous work on the subclones within Escherichia coli ST131 predominantly involved isolates from Western countries. This study assessed the prevalence and antimicrobial resistance attributed to this clonal group. A total of 340 consecutive, non-duplicated urinary E. coli isolates originating from four clinical laboratories in Hong Kong in 2013 were tested. ST131 prevalence among the total isolates was 18.5 % (63/340) and was higher among inpatient isolates (23.0 %) than outpatient isolates (11.8 %, P<0.001), and higher among isolates from patients aged ≥65 years than from patients aged 18–50 years and 51–64 years (25.4 vs 3.4 and 4.0 %, respectively, P<0.001). Of the 63 ST131 isolates, 43 (68.3 %) isolates belonged to the H30 subclone, whereas the remaining isolates belonged to H41 (n = 17), H54 (n = 2) and H22 (n = 1). All H30 isolates were ciprofloxacin-resistant, of which 18.6 % (8/43) belonged to the H30-Rx subclone. Twenty-six (41.3 %) ST131 isolates were ESBL-producers, of which 19 had bla CTX-M-14 (12 non-H30-Rx, two H30-Rx and five H41), six had bla CTX-M-15 (five non-H30-Rx and one H30-Rx) and one was bla CTX-M-negative (H30). In conclusion, ST131 accounts for a large share of the antimicrobial-resistant E. coli isolates from geriatric patients. Unlike previous reports, ESBL-producing ST131 strains mainly belonged to non-H30-Rx rather than the H30-Rx subclone, with bla CTX-M-14 as the dominant enzyme type.postprin

Draft Genome Sequences of Two Multidrug-Resistant Acinetobacter baumannii Strains of Sequence Type ST92 and ST96

The global epidemiology of multidrug-resistant Acinetobacter baumannii is dominated by a limited number of clones. Here, we announce the draft genome sequences of two multidrug-resistant A. baumannii strains, 1H8 and 4A3, representing the major epidemic clones, sequence type 92 (ST92) and ST96, respectively.link_to_OA_fulltex

Biosensor for rapid determination of 3-hydroxybutyrate using bienzyme system

A bienzyme-based Clark electrode was developed for the determination of 3-hydroxybutyrate. This sensor is based on the specific dehydrogenation by 3-hydroxybutyrate dehydrogenase (HBDH, E.C. 1.1.1.30) in combination with salicylate hydroxylase (SHL E.C. 1.14.13.1). The enzymes were entrapped by a poly(carbamoyl) sulfonate (PCS) hydrogel on a Teflon membrane. The principle of the determination scheme is as follows: the specific detecting enzyme, HBDH, catalyses the specific dehydrogenation of 3-hydroxybutyrate consuming NAD(+). The products, NADH, initiate the irreversible decarboxylation and the hydroxylation of salicylate by SHL in the presence of oxygen. SHL forces the equilibrium of dehydrogenation of 3-hydroxybutyrate by HBDH to the product side by consuming NADH. Dissolved oxygen acts as an essential material for SHL during its enzymatic reactions. This results in a detectable signal due to the SHL-enzymatic consumptions of dissolved oxygen in the measurement of 3-hydroxybutyrate. Interferences from different amino acids and electroactive substances were found to be minimal due to the specificity of HBDH and the application of a Teflon membrane. The sensor has a fast response (2 s) and short recovery time (2 min) with a linear range between 8 and 800 mu M 3-hydroxybutyrate and a detection limit of 3.9 mu M. A good agreement (R-2 = 0.9925) with theoretical calculation was obtained in spiked serum sample measurements. (c) 2005 Elsevier B.V. All rights reserved

Dissemination of plasmid-mediated fosfomycin resistance fosA3 among multidrug-resistant Escherichia coli from livestock and other animals.

Aims: To investigate plasmid-mediated fosfomycin resistance related to fosA3 in Escherichia coli isolates collected from different animals in Hong Kong, China, 2008-2010. Methods and Results: In total, 2106 faecal specimens from 210 cattle, 214 pigs, 460 chickens, 398 stray cats, 368 stray dogs and 456 wild rodents were cultured. The faecal colonization rates of fosfomycin-resistant E. coli were as follows: 11·2% in pigs, 8·6% in cattle, 7·3% in chickens, 2·4% in dogs, 0·8% in cats and 1·5% in rodents. The cultures yielded 1693 isolates of which 831 were extended-spectrum β-lactamases (ESBL) producers. Fosfomycin-resistant isolates were more likely than fosfomycin-susceptible isolates to be producers of ESBL and to have resistance to chloramphenicol, ciprofloxacin, cotrimoxazole, gentamicin and tetracycline. Of the 101 fosfomycin-resistant isolates, 97 (96·0%) isolates were fosA3 positive and 94 (93·1%) were blaCTX-M positive. PCR mapping showed that the fosA3-containing regions were flanked by IS26, both upstream and downstream in 81 (83·5%) isolates, and by an upstream blaCTX-M-14-containing transposon-like structure (ΔISEcp1-blaCTX-M-14-ΔIS903 or ISEcp1-IS10 -blaCTX-M-14-ΔIS903) and a downstream IS26 in 14 (14·4%) isolates. For the remaining two isolates, fosA3 was flanked by a downstream IS26 but the upstream part cannot be defined. In a random subset of 18 isolates, fosA3 was carried on transferable plasmids with sizes of 50-200kb and the following replicons: F2:A-B- (n=3), F16:A1:B- (n=2), F24:A-B- (n=1), N (n=1), B/O (n=1) and untypeable (n=3). Significance and Impact of the Study: This study demonstrates the emergence of fosA3-mediated fosfomycin resistance among multidrug-resistant E. coli isolates from various animals. IS26 transposon-like structures might be the main vehicles for dissemination of fosA3. © 2012 The Society for Applied Microbiology

Highly conjugative IncX4 plasmids carrying blaCTX-M in Escherichia coli from humans and food animals

This study investigated the prevalence of IncX plasmid subtypes in commensal and pathogenic Escherichia coli isolates and the biological features of the IncX4 subtype. Two hundred and twenty-five E. coli isolates from multiple sources (47 chickens, 41 pigs, 30 cattle and 107 humans) obtained during the period 2006-2012 were tested for the presence of IncX1 to IncX5. Overall, the prevalence of IncX plasmids in chicken, pig, cattle and human isolates were 21.2% (10/47), 19.5% (8/41), 3.3% (1/30) and 4.8% (5/107), respectively. IncX4 was the most common subtype, followed by IncX1 and IncX3, while no IncX2 or IncX5 were found. Seven out of 16 (43.8 %) IncX4 plasmids were found to carry blaCTX-M genes and six of them originating from different host sources (four chickens, one pig and one human) had identical or highly similar RFLP patterns. Three IncX4 plasmids carrying blaCTX-M from different host sources were investigated further. It was found that the IncX4 plasmids had little effect on bacterial host growth parameters after their introduction to J53 recipients. Conjugation experiments demonstrated that the IncX4 plasmids could be efficiently transferred at 30-42 °C at rates which were generally 102-105-fold higher than those for the epidemic IncFII plasmid carrying blaCTX-M (pHK01). In conclusion, the IncX plasmids are more common than previously recognized. The efficient transfer of IncX4 plasmid at different temperatures and the lack of fitness burden on bacterial hosts highlight the ability of this plasmid replicon to be an important vehicle for dissemination of antimicrobial resistance. © 2014 The Authors

Clonality and antimicrobial susceptibility of Staphylococcus aureus and methicillin-resistant S. aureus isolates from food animals and other animals

Out of 3,081 animals studied, 24.9% of pigs, 4.7% of chickens, 6.3% of dogs, 10.5% of cats, and 7.1% of rodents were Staphylococcus aureus positive. Prevalence of methicillin-resistant S. aureus (MRSA) was high in pigs (animals, 21.3%; batches, 46.5%), with all MRSA isolates and most methicillin-sensitive S. aureus isolates belonging to clonal complex 9 (CC9) and being multidrug resistant. The predominant S. aureus CCs among dog and cat isolates were similar. Among rodent isolates, CC398 predominated, with spa t034 the most frequent spa type detected