Reaction or infection: topical chloramphenicol treatment

Electrochemical aptasensor based on gold nanoparticle decorated Ti3C2Tx nanocomposites for chloramphenicol detection

Using gold (Au) nanoparticle decorated Ti₃C₂T_x (Ti₃C₂T_x-Au) nanocomposites, a highly sensitive electrochemical aptasensor for the effective detection of chloramphenicol has been developed. As a two-dimensional layered material, the prepared composite not only provides high surface area, good conductivity, and thermal stability but also substantial binding sites for aptamers with high sensitivity and selectivity for the accurate determination of chloramphenicol. Interestingly, the conductivity and active sites were enhanced by freeze-drying Ti₃C₂T_x and in situ formation of Ti₃C₂T_x-Au nanocomposite. The fabricated aptasensor exhibited a very low detection limit (S/N ≥ 3) of 13.18 fg mL^-1 with a linear range of 1 ~ 700 pg mL^-1 and correlation coefficient of 0.9992. The fabricated aptasensor demonstrated an excellent reproducibility, repeatability, long-term stability, and high selectivity toward chloramphenicol. Further, the aptasensor was applied to real milk samples, and the recoveries were ranged from 98.93 to 101.93%.

Antibiotic resistance in ocular bacterial infections: an integrative review of ophthalmic chloramphenicol

INTRODUCTION

Chloramphenicol is a broad-spectrum antibiotic widely used for treating ophthalmic infections, but concerns about rising bacterial resistance to chloramphenicol have been observed due to its frequent use as an over-the-counter medication. This review assessed the common ophthalmic bacterial pathogens, their chloramphenicol resistance mechanisms, and rates of drug resistance.

METHODS

PubMed and Google Scholar databases were searched for relevant publications from the years 2000 to 2022, bordering on ophthalmic bacterial infections, chloramphenicol susceptibility profiles, and drug resistance mechanisms against chloramphenicol. A total of 53 journal publications met the inclusion criteria, with data on the antibiotic susceptibility profiles available in 44 of the reviewed studies, which were extracted and analyzed.

RESULTS

The mean resistance rates to chloramphenicol from antibiotic susceptibility profiles varied between 0% and 74.1%, with the majority of the studies (86.4%) showing chloramphenicol resistance rates below 50%, and more than half (23 out of 44) of the studies showed resistance rates lower than 20%. The majority of the publications (n = 27; 61.4%) were from developed nations, compared to developing nations (n = 14; 31.8%), while a fraction (n = 3; 6.8%) of the studies were regional cohort studies in Europe, with no country-specific drug resistance rates. No pattern of cumulative increase or decrease in ophthalmic bacterial resistance to chloramphenicol was observed.

CONCLUSIONS

Chloramphenicol is still active against ophthalmic bacterial infections and is suitable as a topical antibiotic for ophthalmic infections. However, concerns remain about the drug becoming unsuitable in the long run due to some proof of high drug resistance rates.

Comparative genetic characterization of CMY-2-type beta-lactamase producing pathogenic Escherichia coli isolated from humans and pigs suffering from diarrhea in Korea

BACKGROUND

Pathogenic Escherichia coli are an important cause of bacterial infections in both humans and pigs and many of antimicrobials are used for the treatment of E. coli infection. The objective of this study was to investigate the characteristics and relationship between humans and pigs regarding third-generation cephalosporin resistance and CMY-2-producing E. coli in Korea.

RESULTS

All 103 third-generation cephalosporin-resistant E. coli isolates showed multidrug resistance. Also, except for β-lactam/β-lactamase inhibitor combinations, all antimicrobials resistant rates were higher in pigs than in humans. A total of 36 isolates (humans: five isolates; pigs: 31 isolates) were positive for the CMY-2-encoding genes and thirty-two (88.9%) isolates detected class 1 integrons with 10 different gene cassette arrangements, and only 1 isolate detected a class 2 integron. The most common virulence genes in pigs were LT (71.0%), F18 (51.6%), and STb (51.6%), while stx2 (80.0%) was the most frequently detected gene in humans. Stx2 gene was also detected in pigs (6.5%). Interestingly, 36 CMY-2-producing E. coli isolates showed a high diversity of sequence types (ST), and ST88 was present in E. coli from both pigs (11 isolates) and humans (one isolate).

CONCLUSION

Our findings suggest that a critical need for comprehensive surveillance of third-generation cephalosporin resistance is necessary to preserve the usefulness of third-generation cephalosporins in both humans and pigs.

Genetic Characterization of Fluoroquinolone Resistance in Salmonella enterica Serovar Gallinarum Isolates from Chicken in Korea

Salmonella enterica serovar Gallinarum is a nonmotile host-adapted Salmonella that causes fowl typhoid (FT), and an outbreak of FT is characterized by anorexia, greenish-yellow diarrhea, paleness, and sudden death with high mortality in poultry. To control and treat FT in commercial chickens, fluoroquinolones are widely used in Korea. This study aimed to investigate the genetic characteristics of fluoroquinolone-resistant Salmonella Gallinarum isolates from 2014-18 from chicken in Korea. A total of 35 ciprofloxacin (CIP)-resistant Salmonella Gallinarum was tested, and 22 (62.9%) isolates were observed to have multidrug resistance. All isolates had a mutation at the Ser83 or Asp87 codon in the gyrA gene, whereas three isolates had only double mutations at Ser83 → Phe and Asp87 → Asn or Ser83 → Phe and Asp87 → Gly. Minimum inhibitory concentrations of isolates with double mutations were relatively higher (≥8 mg/L for CIP and ≥16 mg/L for enrofloxacin) than those of other isolates with a single mutation in gyrA. Among 35 CIP-resistant Salmonella Gallinarum, plasmid-mediated quinolone resistance genes were detected in six (17.1%) isolates, and qnrB and qnrS were detected in four and two isolates, respectively. In the distribution of antimicrobial resistance genes in 35 CIP-resistant Salmonella Gallinarum, ant(2″)-I (54.3%) was the most prevalent gene, followed by TEM-1 (14.3%), sul1 (11.4%), and cmlA (5.7%). Fifteen (42.9%) of the 35 CIP-resistant Salmonella Gallinarum also carried class 1 integrons, which showed five types of resistance gene cassettes: aadA2 (7 isolates), aadA2 + dfrA12 (5 isolates), and aadA1 + aad A2 (3 isolates). Among plasmid replicons, 23 isolates (65.7%) carried five different plasmid replicons: Frep (9 isolates), FIB (7 isolates), FIIA (6 isolates), B/O (4 isolates), and I1 (3 isolates). These results suggest that continued monitoring of fluoroquinolone resistance is necessary to preserve the effectiveness of fluoroquinolones in poultry and to surveil the transmission to humans through the food chain.

Super-hydrophilic and high strength polymeric foam dressings of modified chitosan blends for topical wound delivery of chloramphenicol

In the present study polymer blends based on chitosan (CS) and its derivatives with trans-aconitic (t-Acon) acid and another with trimellitic (TRM) anhydride, were prepared for topical wound delivery of chloramphenicol (CHL). FT-IR spectroscopy revealed the successful grafting of t-Acon acid or TRM anhydride into CS macromolecules at molar ratios 1:1 and 1:0.5, while powder X-ray diffraction (XRD) analysis showed that the prepared materials were amorphous. Neat chitosan and its grafted derivatives were mixed in different ratios (25/75, 50/50 and 75/25 w/w) in order to prepare suitable blends. Scanning electron microscopy (SEM) showed that the formed blends after freeze-drying had a sponge-like structure, while thermogravimetric analysis (TGA) verified their thermal stability. All blends are miscible in studied compositions and have extensive swelling and much better mechanical properties than neat CS. In a further step, the obtained porous sponges prepared from CS/CS-derivatives 50/50 w/w were loaded with Chloramphenicol (10, 20 and 30 wt%), a broad-spectrum antibiotic, and the prepared dressings were evaluated in terms of FT-IR, XRD, SEM, and in vitro drug dissolution. An initial burst release followed by a quasi-Fickian diffusion driven sustained release phase was observed while the addition of chloramphenicol gives high antimicrobial properties to all dressings.

Efficacy and adverse effects of topical chloramphenicol ointment use for surgical wounds: a systematic review

BACKGROUND

Chloramphenicol ointment is often used in plastic and dermatologic surgery as a topical antibiotic for surgical wounds, but evidence regarding its efficacy and side effects is lacking. In addition, anecdotal fear of aplastic anaemia exists from the oral use of this drug. We performed a systematic review of the literature to assess the efficacy and side effect profile of topical chloramphenicol ointment on non-ocular surgical wounds.

METHODS

A systematic search of MEDLINE, EMBASE and the Cochrane Library from inception until 4 September 2017 was undertaken. Clinical studies of topical chloramphenicol ointment use on surgical wounds were included. Studies looking only at ocular use or those not available in full text or English were excluded. The review was conducted adhering to PRISMA guidelines.

RESULTS

After full-text review, five articles were included. Two were randomized controlled trials, one was retrospective case control and two were case studies. There was evidence that chloramphenicol ointment use on surgical wounds produced a non-statistically significant reduction in infection rates. Delayed hypersensitivity and acute oesophagitis were noted as potential side effects of non-ocular topical use. Aplastic anaemia was not reported.

CONCLUSION

There is a paucity of clinical data regarding the use of topical chloramphenicol ointment on surgical wounds. Further randomized controlled trials may be beneficial in order to support or refute its use in this setting.

LL-37-derived membrane-active FK-13 analogs possessing cell selectivity, anti-biofilm activity and synergy with chloramphenicol and anti-inflammatory activity

Although the human-derived antimicrobial peptide (AMP) LL-37 has potent antimicrobial and anti-inflammatory activities, its therapeutic application is limited by its low cell selectivity and high production cost due to its large size. To overcome these problems, we tried to develop novel LL-37-derived short α-helical AMPs with improved cell selectivity and without a significant loss of anti-inflammatory activity relative to that of parental LL-37. Using amino acid substitution, we designed and synthesized a series of FK13 analogs based on the sequence of the 13-meric short FK13 peptide (residues 17-29 of LL-37) that has been identified as the region responsible for the antimicrobial activity of LL-37. Among the designed FK13 analogs, FK-13-a1 and FK-13-a7 showed high cell selectivity and retained the anti-inflammatory activity. The therapeutic index (a measure of cell selectivity) of FK-13-a1 and FK-13-a7 was 6.3- and 2.3-fold that of parental LL-37, respectively. Furthermore, FK-13-a1 and FK-13-a7 displayed more potent antimicrobial activity against antibiotic-resistant bacteria including MRSA, MDRPA, and VREF, than did LL-37. In addition, FK-13-a1 and FK-13-a7 exhibited greater synergistic effects with chloramphenicol against MRSA and MDRPA and were more effective anti-biofilm agents against MDRPA than LL-37 was. Moreover, FK-13-a1 and FK-13-a7 maintained their activities in the presence of physiological salts and human serum. SYTOX green uptake, membrane depolarization and killing kinetics revealed that FK13-a1 and FK13-a7 kills microbial cells by permeabilizing the cell membrane and damaging membrane integrity. Taken together, our results suggest that FK13-a1 and FK13-a7 can be developed as novel antimicrobial/anti-inflammatory agents.

Synergistic effect of haloduracin and chloramphenicol against clinically important Gram-positive bacteria

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Haloduracin and chloramphenicol exhibited synergistic effect against pathogens.

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The synergy indicates possibility of reducing the effective dose of chloramphenicol.

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Reduction of chloramphenicol dose minimizes its negative side effects.

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This shows a new window of using antibiotics and bacteriocins in combination therapy.

The emergence of drug-resistant pathogens has triggered the search for more efficient antimicrobial agents and formulations for treatment of infections. In recent years, combination therapy has become one of the effective clinical practices in treating infections. The present study deals with the effect of haloduracin, a lantibiotic bateriocin and chloramphenicol against clinically important bacteria. The combined use of haloduracin and chloramphenicol resulted in remarkable synergy against a spectrum of microorganisms including strains of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis and different groups of Streptococcus. The synergy allowed using these antimicrobial agents at substantially reduced concentrations without compromising their efficiency. Use of lower doses of chloramphenicol can avoid the severity of its side effects. In addition to minimizing undesirable side effects of some drugs, this approach brings the possibility of using antibiotics that are no longer effective due to drug resistance. Furthermore, the observed synergy between haloduracin and chloramphenicol opens a new window of using bacteriocins and antibiotics in combination therapy of infections.

Otitis externa complicated with chloramphenicol ear drops-induced perichondritis

Otitis externa is a common condition of the ear. It is manifested as narrowing of the lumen owing to the edematous swelling of the ear canal lining. Perichondritis may occur independently or as a complication of the otitis externa. We report a case of perichondritis after using a topical ear drop. Changing the medication provides immediate resolution of the condition.