Enrofloxacin in therapeutic doses alters cytokine production by porcine PBMCs induced by lipopolysaccharide

The effect of enrofloxacin on cytokine secretion by porcine peripheral blood mononuclear cells (PBMCs) was studied. Twenty 8–20-week-old pigs were randomly divided into two groups: control (C, n?=?10) and experimental (E, n?=?10) were used. Pigs from group E received enrofloxacin at therapeutic dose for 5 consecutive days. Blood samples were collected at 0 (before antibiotic administration), 2, 4 (during antibiotic therapy) 6, 9, 14 21, 35, 49, and 63?d of study (after treatment). PBMCs of pigs from both groups were incubated with or without lipopolysaccharide (LPS). Ex vivo production on interleukin (IL)-4, IL-6, IL-10, INF-γ, and TNF-α were analyzed using ELISA assay. Intramuscular administration of enrofloxacin to healthy pigs for 5 consecutive days induced a transitory reduction of the ex vivo response of PBMCs to LPS in terms of IL-6 and TNF-α secretion. The level of IL-6 returned to day 0 level shortly after end of treatment, while the TNF-α production remained reduced 10 d after the end of treatment. Our results indicate that enrofloxacin given in vivo in therapeutic doses has an immunomodulatory effect through its capacity to inhibit ex vivo secretion of IL-6 and TNF-α by porcine PBMC after LPS stimulation.     

Characterization of chromosomal qnrB and ampC alleles in Citrobacter freundii isolates from different origins

The association of ESBLs (extended-spectrum beta-lactamases)/pAmpCs (plasmid-mediated AmpC β-lactamases) with PMQR (plasmid mediated quinolone resistance) in gram-negative bacteria has been of great concern. The present study was performed to characterize the diversity, gene location, genetic context, and evolution of ampC and qnrB alleles in isolates of Citrobacter freundii. Fifteen isolates of C. freundii were identified from a total of 788 isolates of Enterobacteriaceae derived from humans, animals, animal food products, and the environment between 2010 and 2012. Co-existence of qnrB/ΔqnrB with ampC was detected in all C. freundii isolates. Both ampC and qnrB genes were found to be located on the chromosome, but were distantly separated on the chromosome. Seven and six novel alleles were discovered for the 10 ampC and qnrB variants detected in this study, respectively. Phylogenetic analysis showed that the new alleles differed a little from the variants of ampC/qnrB previously described in this genus. The genetic context surrounding ampC genes was AmpR-AmpC-Blc-SugE. However, five different genetic contexts surrounding qnrB/ΔqnrB genes were observed, but they occurred in all cases between the pspF and sapA genes. Additionally, cloning experiments showed that the regions containing different qnrB alleles, even with different genetic contexts, contributed to the reduction of quinolone susceptibility. Our results showed that the chromosomal ampC and qnrB alleles are closely related to C. freundii. However, unlike ampC, qnrB alleles seemed to be related to the genetic contexts surrounding them. The evolution of these two genes in C. freundii isolates might be through different pathways.     

Spontaneous bilateral Achilles tendon rupture in a patient treated with oral levofloxacin

A case of bilateral rupture of the Achilles tendon in a patient treated with levofloxacin for cystitis is reported. A 76-year-old woman suddenly developed painful ankles one day after levofloxacin treatment. Drug therapy was switched to amoxicillin/clavulanate on the fourth day. Sonography revealed a serious condition of tendinosis with complete bilateral full-thickness rupture on day 6. Tendons were both repaired in the same surgical session. Pathological anatomy of the specimens reported fatty tissue lobules with panniculitis and histiocytosis. Ankles were immobilized postoperatively with a plaster cast. Achilles tendon rupture may occur as an adverse side effect of short-term use of levofloxacin, a fluoroquinolone antibiotic. This adverse effect is a rare and poorly understood complication of this antibiotic therapy. A review of the literature is provided.     

左氧氟沙星治疗伤寒临床疗效和体外抗菌活性研究

评价左氧氟沙星治疗伤寒的临床疗效和体外抗菌活性，方法：以国产和进口左氧氟沙星片剂做随机对照试验治疗急性伤寒共３０例，用药量均为２００ｍｇ，每日２次，疗程７ｄ，结果：两种药物均获得了良好的临床疗效，临床治愈率和细菌清除率均为１００％，国产和进口左氧氟沙星在临床疗效和细菌学疗效方面均无差异，两种药对伤寒杆菌的ＭＩＣ９０均为０．１２５ｍｇ／Ｌ。全部病例未见明显不良反应发生。．     

GyrA and/or ParC alterations of Haemophilus influenzae strains isolated from the urethra of men with acute urethritis

Of 73 clinical strains of Haemophilus influenzae isolated from the urethra of men with urogenital infections, we enrolled 6 strains (8.2%) with levofloxacin (LVFX) minimum inhibitory concentrations (MICs) of ≥0.03 μg/ml in this study. All the strains were isolated from non-gonococcal urethritis (NGU). We amplified the quinolone resistance-determining region of the gyrA gene and the analogous region of the parC gene from bacterial DNAs by PCR and sequenced the PCR products. Two strains with a LVFX MIC of 0.03 μg/ml had an amino acid change of Asp88 to Gly in GyrA. One with a LVFX MIC of 0.06 μg/ml had a change of Asp88 to Tyr in GyrA. Two with respective LVFX MICs of 0.12 and 0.25 μg/ml had a change of Ser84 to Leu in GyrA. One with a LVFX MIC of 1 μg/ml had changes of Ser84 to Leu in GyrA and of Ser84 to Ile in ParC. Multilocus sequence typing showed two strains with a change of Asp88 to Gly in GyrA had the same sequence type, but the others had sequence types different from each other. Single amino acid changes in GyrA alone or single changes in both GyrA and ParC could contribute to decreased susceptibility to fluoroquinolones in H. influenzae isolates from NGU. Most of the isolates with GyrA and/or ParC alterations would be multiclonal. The prevalence of such isolates would be relatively low, and they would still be susceptible to fluoroquinolones commonly prescribed for treatment of NGU.     

Investigation of the susceptibility trends in Japan to fluoroquinolones and other antimicrobial agents in a nationwide collection of clinical isolates: A longitudinal analysis from 1994 to 2016

The susceptibilities of clinical isolates to fluoroquinolones and other antimicrobial agents were surveyed to obtain an accurate understanding of trends in incidence and antimicrobial resistance. The samples were collected from across Japan, biennially or triennially, between 1994 and 2016 and a defined level of resistance to fluoroquinolone was determined.Streptococcus pneumoniae, Streptococcus pyogenes and Haemophilus influenzae exhibited stable and high rates of susceptibility to fluoroquinolones over the period examined. For methicillin-resistant Staphylococcus aureus the rate of resistance to levofloxacin and ciprofloxacin was 81.3–93.5% and 83.2–94.2%, respectively, which was markedly higher than that of methicillin-susceptible S. aureus, while sitafloxacin-resistant methicillin-susceptible and methicillin-resistant S. aureus were isolated at 0.3–0.7% and 16.9–36.5%, respectively. The rate of levofloxacin or ciprofloxacin-resistant Escherichia coli increased from around 2–3% between 1994 and 1998 to around 35% in 2016, but the rate of fluoroquinolone-susceptible Klebsiella pneumoniae stayed high at over 94.6% during the study period. Although no fluoroquinolone-resistance in clinical isolates of Salmonella spp. was detected from 1994 to 2002, the resistance rate increased slightly after 2004 and reached to 1.9%–4.7% in 2016. The rate of fluoroquinolone-susceptible Pseudomonas aeruginosa isolated from urinary tract and respiratory tract infections improved during the period examined from 41.8–67.0% to 91.2–94.2%, and from 78.9-88.5% to 90.1–94.6%, respectively. Against Acinetobacter spp., the susceptibility rate of fluoroquinolones was almost constant at around 90%, but one multidrug-resistant isolate was detected in 2013. Overall, the susceptibility to fluoroquinolones was maintained over 20 years against tested bacteria except for MRSA and E. coli.     

In-vitro activity of moxifloxacin and other fluoroquinolones against Chlamydia species

The in-vitro activity of moxifloxacin, a new fluoroquinolone, against Chlamydia species was investigated. The minimal inhibitory concentration of moxifloxacin for 10 standard strains of different Chlamydia species and 15 wild-type strains of Chlamydia pneumoniae isolated in Japan, which were morphologically different from clinical isolates from the United States, ranged from 0.031 to 0.125 μg/ml. The activity of moxifloxacin was almost the same as those of sparfloxacin, and it was 16, 8, 2, and 2 times more active than ciprofloxacin, levofloxacin, grepafloxacin, and tosufloxacin, respectively. The minimal chlamydiacidal concentration of moxifloxacin ranged from 0.031 to 0.125 μg/ml. These results suggest that moxifloxacin has potential effects against Chlamydia species. Received: August 23, 2001 / Accepted: October 29, 2001     

Synthesis and in vitro antibacterial activity of 7-(4-alkoxyimino-3-amino-3-methylpiperidin-1-yl)fluoroquinolone derivatives

A series of novel 7-(4-alkoxyimino-3-amino-3-methylpiperidin-1-yl)fluoroquinolone derivatives were designed, synthesized and characterized by ¹H NMR, MS and HRMS. These fluoroquinolones were evaluated for in vitro antibacterial activity against representative Gram-positive and Gram-negative strains. All of the title compounds have considerable activity against the twelve strains, and exhibit exceptional potency in inhibiting the growth of Staphylococcus aureus, Staphylococcus epidermidis and Klebsiella pneumoniae (minimum inhibitory concentration (MIC): 0.06–8 μg/mL). The most active compound 17 is 4-fold more potent than levofloxacin against S. aureus and S. epidermidis, 32-fold more potent than levofloxacin against Streptococcus pneumoniae, and 16-fold more potent than IMB against K. pneumoniae.     

Synthesis and In Vitro Antibacterial Activity of 7‐(3‐Alkoxyimino‐4‐methyl‐4‐methylaminopiperidin‐1‐yl)‐fluoroquinolone Derivatives

A series of novel 7‐(3‐alkoxyimino‐4‐methyl‐4‐methylaminopiperidin‐1‐yl)fluoroquinolone derivatives were designed, synthesized, and characterized by ¹H‐NMR, MS, and HRMS. These fluoroquinolones were evaluated for their in‐vitro antibacterial activity against representative Gram‐positive and Gram‐negative strains. Generally, all of the target compounds have considerable antibacterial activity against the tested forty strains, and exhibit exceptional potency in inhibiting the growth of methicillin‐sensitive Staphylococcus aureus (MSSA) and methicillin‐resistant S. aureus (MRSA) ATCC33591 (MICs: 0.06 to 2 μg/mL). In particular, compounds 14 , 19 , 28 , and 29 are fourfold more potent than ciprofloxacin against MSSA 08‐49. Compounds 23 , 26 , and 27 are twofold more potent than ciprofloxacin against MRSA ATCC33591 and MSSA ATCC29213. In addition, compound 14 exhibits excellent activity (MIC: 0.06 μg/mL) against Acinetobactes calcoaceticus, which is two‐ to 16‐fold more potent than the reference drugs gemifloxacin, levofloxacin, and ciprofloxacin.     

In vivo and in vitro effects of fluoroquinolones on lipopolysaccharide-induced pro-inflammatory cytokine production

Fluoroquinolones have been reported to affect cytokine production in vitro. We investigated the effects of fluoroquinolones on lipopolysaccharide (LPS)-induced inflammatory cytokine production in vivo and in vitro. LPS was administered to mice treated with ciprofloxacin, gatifloxacin, norfloxacin, and levofloxacin, and the serum levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6) were measured. In addition, peritoneal macrophages collected from mice were treated with the four fluoroquinolones for 1 h, followed by the addition of LPS, and the TNF-α, IL-1β, and IL-6 levels in culture fluid were measured. In LPS-treated mice, ciprofloxacin, gatifloxacin, and norfloxacin (100 mg/kg) significantly reduced the serum TNF-α level (6.8%–63.6% of control). Levofloxacin at 100 mg/kg did not affect the TNF-α level, whereas levofloxacin at a lower dose (10 mg/kg) significantly increased the level. All four fluoroquinolones (100 mg/kg) investigated in this study tended to decrease the serum IL-1β levels (65.5%–65.9% of control), but this was not a significant change. The serum IL-6 levels were increased in ciprofloxacin-administered mice, whereas the other fluoroquinolones did not affect the serum IL-6 levels. In mouse peritoneal macrophages, LPS induced TNF-α, IL-1β, and IL-6 production. Ciprofloxacin, gatifloxacin, and norfloxacin (100 μg/ml) inhibited both TNF-α (12.1%–69.0% of control) and IL-1β production (22.1%–68.8% of control). Levofloxacin (100 μg/ml) inhibited IL-1β production (65.0% of control), but not TNF-α production. LPSstimulated IL-6 production was inhibited only by norfloxacin (59.5 % of control). Our in vivo and in vitro results suggest that fluoroquinolones, especially ciprofloxacin, gatifloxacin, and norfloxacin, which have a cyclopropyl group at the N1 position and/or a piperazinyl group at the C7 position, modify inflammatory responses.