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Objectives: To investigate the susceptibility of imipenem-non-susceptible Escherichia coli (INS-EC), Klebsiella pneumoniae (INS-KP), Acinetobacter baumannii (INS-AB) and Pseudomonas aeruginosa (INS-PA) to novel antibiotics., Methods: MICs were determined using the broth microdilution method. Carbapenemase and ESBL phenotypic testing and PCR for genes encoding ESBLs, AmpCs and carbapenemases were performed., Results: Zidebactam, avibactam and relebactam increased the respective susceptibility rates to cefepime, ceftazidime and imipenem of 17 INS-EC by 58.8%, 58.8% and 70.6%, of 163 INS-KP by 77.9%, 88.3% and 76.1% and of 81 INS-PA by 45.7%, 38.3% and 85.2%, respectively. Vaborbactam increased the meropenem susceptibility of INS-EC by 41.2% and of INS-KP by 54%. Combinations of β-lactams and novel β-lactamase inhibitors or β-lactam enhancers (BLI-BLE) were inactive against 136 INS-AB. In 58 INS-EC and INS-KP with exclusively blaKPC-like genes, zidebactam, avibactam, relebactam and vaborbactam increased the susceptibility of the partner β-lactams by 100%, 96.6%, 84.5% and 75.9%, respectively. In the presence of avibactam, ceftazidime was active in an additional 85% of 20 INS-EC and INS-KP with exclusively blaOXA-48-like genes while with zidebactam, cefepime was active in an additional 75%. INS-EC and INS-KP with MBL genes were susceptible only to cefepime/zidebactam. The β-lactam/BLI-BLE combinations were active against INS-EC and INS-KP without detectable carbapenemases. For INS-EC, INS-KP and INS-AB, tigecycline was more active than omadacycline and eravacycline but eravacycline had a lower MIC distribution. Lascufloxacin and delafloxacin were active in <35% of these INS isolates., Conclusions: β-Lactam/BLI-BLE combinations were active in a higher proportion of INS-EC, INS-KP and INS-PA. The susceptibility of novel fluoroquinolones and tetracyclines was not superior to that of old ones., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objectives: We aimed to determine susceptibilities of Elizabethkingia spp. to 25 commonly tested and 8 novel antibiotics, and to compare the performance of different susceptibility testing methods., Methods: Clinical isolates of Elizabethkingia spp., Chryseobacterium spp. and Flavobacterium spp. collected during 2002-18 (n = 210) in a nationwide surveillance programme in Taiwan were speciated by 16S rRNA sequencing. MICs were determined by broth microdilution. The broth microdilution results of 18 common antibiotics were compared with those obtained by the VITEK 2 automated system., Results: Among the Elizabethkingia spp. identified (n = 108), Elizabethkingia anophelis was the most prevalent (n = 90), followed by Elizabethkingia meningoseptica (n = 7) and Elizabethkingia miricola cluster [E. miricola (n = 6), Elizabethkingia bruuniana (n = 3) and Elizabethkingia ursingii (n = 2)]. Most isolates were recovered from respiratory or blood specimens from hospitalized, elderly patients. PFGE showed two major and several minor E. anophelis clones. All isolates were resistant to nearly all the tested β-lactams. Doxycycline, minocycline and trimethoprim/sulfamethoxazole inhibited >90% of Elizabethkingia spp. Rifampin inhibited E. meningoseptica (100%) and E. anophelis (81.1%). Fluoroquinolones and tigecycline were active against E. meningoseptica and E. miricola cluster isolates. Novel antibiotics, including imipenem/relebactam, meropenem/vaborbactam, ceftazidime/avibactam, cefepime/zidebactam, delafloxacin, eravacycline and omadacycline were ineffective but lascufloxacin inhibited half of Elizabethkingia spp. The very major discrepancy rates of VITEK 2 were >1.5% for ciprofloxacin, moxifloxacin and vancomycin. Major discrepancy rates were >3% for amikacin, tigecycline, piperacillin/tazobactam and trimethoprim/sulfamethoxazole., Conclusions: MDR, absence of standard interpretation criteria and poor intermethod concordance necessitate working guidelines to facilitate future research of emerging Elizabethkingia spp., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Aims: To study the association between number and positions of mutations with MICs of fluoroquinolone non-susceptible Haemophilus influenzae., Methods and Results: More than 40% of 48 H. influenzae isolated from nursing home residents were not susceptible to fluoroquinolone. Amino acid changes in the quinolone resistance determining regions, and correlation with MICs and inhibition zone diameters were analysed. All isolates with reduced susceptibility to fluoroquinolones (MIC ≥0·125 µg ml -1 ) had at least one mutation in gyrA at position 84 and were resistant to nalidixic acid. Compared to isolates with reduced susceptibility, resistant isolates were associated with mutations in gyrA at positions 88 and 134, and in parC at position 88 (P < 0·001). Inhibition zone diameter for nalidixic acid disk ≥23 mm may detect susceptible isolates., Conclusions: Reduced susceptibility to fluoroquinolones was associated with mutations at position 84 in gyrA. A further increase in fluoroquinolone MIC was associated with mutations in gyrA at positions 88 and 134, and parC at position 88., Significance and Impact of the Study: Due to limited resistant H. influenzae strains, prior studies on association between positions of mutations and fluoroquinolone MICs were inconclusive. The comparison of mutations between isolates with susceptibility, reduced susceptibility and high resistance supported the importance of the present study., (© 2020 The Society for Applied Microbiology.)

Objectives: This study investigated the trend in antimicrobial resistance among group B Streptococcus (GBS) from a national surveillance programme in Taiwan and delineated characteristics of and factors associated with levofloxacin-resistant isolates., Methods: Clinical isolates of all sample types and patient groups were collected from multiple hospitals biennially between 2002 and 2012. Susceptibilities to different antibiotics were determined by broth microdilution. Molecular studies of levofloxacin-resistant isolates included serotyping, PFGE, mutations in the QRDRs and MLST., Results: A total of 1559 isolates were tested and all remained susceptible to penicillin, cephalosporins, meropenem and vancomycin. However, levofloxacin resistance increased from 2.2% (range 0%-3.3%) in 2002-06 to 6.2% (5.9%-7.5%) in 2008-12 (P = 0.016). Among the 88 levofloxacin-resistant isolates, the majority (79.5%) had the GyrA(S81L)+ParC(S79F/Y) double mutations and most (54.5%) were also resistant to clindamycin, erythromycin and tetracycline. The predominant genotype of the levofloxacin-resistant isolates was ST19/serotype III (43.2%). Four previously unreported genotypes, ST1 and its single-locus variants (ST920 and ST922)/serotype VI (28.4%) and ST1/serotype II (18.2%), were found to have circulated locally. Serotype III isolates were predominately from urine and female genital tract specimens and <65-year-old adult outpatients, while serotype II and VI isolates were mostly from respiratory and urine samples and >65-year-old inpatients. Multivariate analysis revealed that elderly age and respiratory samples were independent factors associated with levofloxacin resistance., Conclusions: Multiclonal emergence and dissemination of levofloxacin-resistant GBS isolates occurred in healthcare and community settings in Taiwan. Continuous molecular-level surveillance is important to detect new epidemic trends., (© The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Objectives: To investigate the link between two NDM-1-positive Acinetobacter isolates from the same hospital, the plasmid profiles of the isolates were examined. These two isolates were found from a surveillance programme within 3 months from two patients without obvious physical contact or hospitalization time overlap., Methods: Antimicrobial susceptibility tests, genome sequencing of both isolates and plasmid transfer experiments were performed. A comparative study of similar plasmids was performed using BLAST analysis., Results: The antimicrobial susceptibility of the isolates (Acinetobacter soli M131 and Acinetobacter pittii MS32) and their Escherichia coli transconjugants revealed a conjugative plasmid that carried the carbapenem resistance determinant. Eleven plasmids were observed in M131 and three in MS32. Each isolate shared an identical plasmid that carried the blaNDM-1 gene. This 47 271 bp plasmid harbours a conserved blaNDM-1-containing region that is flanked by ISAba125 and ISAba11 elements, and also contains a Ti-type conjugative operon. The plasmid is nearly identical in sequence to those of Acinetobacter isolates from China. In contrast to the mobilization of the blaNDM-1 sequence in Enterobacteriaceae, which is mainly by transposition, this plasmid moves as a whole among Acinetobacter species. Consistently, this plasmid was found to transfer effectively by in vitro conjugation to several Acinetobacter species., Conclusions: The clinical and laboratory findings suggest that Acinetobacter species may serve as a reservoir of this blaNDM-1 plasmid. Our study demonstrates the potential of applying genome sequencing to the surveillance of antimicrobial-resistant bacteria., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

The genes lukS-PV and lukF-PV for Panton-Valentine leukocidin (PVL) that confers high virulence to Staphylococcus aureus are located on the prophages (PVL phages) which have been classified into group 1 and 2 sfi21-like Siphoviridae. We report novel PVL phages lysogenized in ST59 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in Japan (JCSC7247) and Taiwan (JCSC5967). The genomes of φ7247PVL and φ5967PVL showed more than 99% identity, and the regions containing the five genes located at both ends of the prophages, int (integrase), hol (holin), ami (amidase), lukS-PV, and lukF-PV, are highly homologous to extant PVL phages. The genes for the structural module are less homologous to these phages, but are highly homologous to non-PVL phages belonging to group 3 Sfi21-like Siphoviridae, for example φN315. Subsequent PCR identification and nucleotide sequencing of an additional 11 Taiwanese ST59 MRSA isolates suggested they all carry the same phage as φ5967PVL, which differed from φ7247PVL by a single base. This study adds evidence to the notion that novel PVL phages would be generated through illegitimate recombination events by acquiring the region at which hol, ami, luk, and int genes would line up upon lytic growth, and suggests that the PVL-positive MRSA clones that have emerged worldwide may carry distinct phages., (© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

Nine isolates of Klebsiella pneumoniae, obtained from one colonized and eight bacteraemic patients on a paediatric ward, were shown to be identical by PFGE, indicating an outbreak. Screening for extended-spectrum beta-lactamase (ESBL) production using the double-disc synergy test, Etest for ESBLs and agar diffusion tests indicated ESBL production. The isolates showed reduced susceptibility to cefotaxime but not to other third-generation cephalosporins. Molecular studies revealed production of TEM-1 and SHV-1 but no ESBLs were identified. Deficiency in expression of an outer membrane protein (OmpK35) was also observed. These observations led us to postulate that the extremely low level of OmpK35 expression and the co-existence of TEM-1 and SHV-1 resulted in an increased MIC of cefotaxime and the false designation of the isolates as ESBL producers. All the infected infants were treated with either third-generation cephalosporins alone or multiple antibiotics including a third-generation cephalosporin, and recovered and were discharged without sequelae.

Outer surface protein A (OspA) is encoded by the ospA gene from Borrelia burgdorferi. This protein induces immunity against infection in mice. The cloning and expression of OspA in Escherichia coli have been previously described, but the secretion of OspA into culture media in E. coli has not yet been reported. In this report we demonstrate that a chimeric OspA protein was secreted into culture media by E. coli when it also harbors the hemolysin secretion genes hlyBD. The OspA fusion protein was also overexpressed from a T7 promoter and purified by immobilized metal ion chromatography. This was possible because the fusion protein contains six histidyl residues in its N-terminus.

Lyme disease was reproduced in specific pathogen-free beagle dogs by exposure to Borrelia burgdorferi-infected ticks (Ixodes dammini). Seroconversion and disease frequency were higher after exposure to infected adult ticks than to infected nymphs. Young pups developed clinical disease more readily than older dogs. The incubation period lasted 2-5 months. Acute recurrent lameness with fibrinopurulent arthritis was the dominant clinical sign. Dogs recovered but developed persistent mild polyarthritis. B. burgdorferi persisted in recovered dogs for at least 1 year. Isolation of B. burgdorferi and detection by polymerase chain reaction was most successful from skin biopsies at the site of the tick bite. Antibody to B. burgdorferi antigens was first detected by ELISA and Western blots by 4-6 weeks after exposure. High serum levels persisted during 17 months of observation. In contrast to infection from ticks, inoculation of dogs with cultured B. burgdorferi resulted in seroconversion with a shorter duration of antibody persistence and no clinical disease.