Microorganisms are the dominant players driving the degradation and transformation of chloramphenicol (CAP) in the environment. However, little bacterial strains are able to efficiently degrade and mineralize CAP, and the CAP degrading pathways mediated by oxidative reactions remain unclear. In this study, a highly efficient CAP-degrading microbial consortium, which mainly consists of Rhodococcus (relative abundance >70%), was obtained through an enrichment process using CAP-contaminated activated sludge as the inoculum. A bacterial strain CAP-2 capable of efficiently degrading CAP was isolated from the consortium and identified as Rhodococcus sp. by 16S rRNA gene analysis. Strain CAP-2 can efficiently degrade CAP under different nutrient conditions. Based on the biotransformation characteristics of the detected metabolite p-nitrobenzoic acid and the reported metabolites p-nitrobenzaldehyde and protocatechuate by strain CAP-2, a new oxidative pathway for the degradation of CAP was proposed. The side chain of CAP was oxidized and broken to generate p-nitrobenzaldehyde, which was further oxidized to p-nitrobenzoic acid. Strain CAP-2 can be used to further study the molecular mechanism of CAP catabolism, and has the potential to be used in in situ bioremediation of CAP-contaminated environment.
Biodegradation, Environmental ; Chloramphenicol ; RNA, Ribosomal, 16S/genetics* ; Rhodococcus/genetics* ; Sewage

OBJECTIVE: To improve and establish the mouse model with aplastic anemia (AA) mediated by Cs γ-ray irradiation combined with cyclophosphamide (CTX) and chloramphenicol (CHL) injection,so as to provide a stable model for studying the pathogenesis and treatment of AA . METHODS: The BALB/c mice were exposed to Cs γ-ray of 3-5 Gy(91 cGy/min) and were intraperitoneally injected with CTX of 25 mg/(kg.d) and CHL of 62.5 mg/(kg.d) at D 4,5 and 6 after irradiation; the WBC, platelet and reticulocyte counts in peripheral blood as well as the mucleated cell count in bone marrow and bone marrow smears were detected . RESULTS: The 3-lineage cells in peripheral blood of BALB/c mouse model with acquired AA were rapidly reduced, especially WBC, platelet and reticulocyte counts were lowest at D 14,the 3-lineage cells in peripheral blood were still severely reduced at D 28; the nucleated cell count in bone marrow significantly dcreased,the bone marrow hyperplasia was reduced or severely reduced; the pathological sections of bone marrow showed the severe reduction of hematopoietic cells and the increased of non-hematopoietic cells such as fat cells. CONCLUSION The mouse model with acquired AA has been established by Cs γ-ray irradiation combined with CTX and CHL injection. All detection indicators of this model reach to diagnostic criteria for acquired AA,therefore this mouse model may be used as the model for study of pathogenesis and treatment of acquired AA.
Anemia, Aplastic ; Animals ; Chloramphenicol ; Cyclophosphamide ; Gamma Rays ; Mice ; Mice, Inbred BALB C

BACKGROUND: Campylobacter jejuni is an important food-borne pathogen that causes human gastroenteritis. This study was conducted to investigate the incidence of isolation, antimicrobial susceptibility pattern, and C. jejuni genotype from diarrhea patients in Busan, Korea. METHODS: A total of 97 C. jejuni were isolated from diarrhea patients during five food-borne outbreaks from 2014 to September 2017. Antimicrobial susceptibility tests were carried out by the broth microdilution method for ciprofloxacin (CIP), nalidixic acid (NAL), tetracycline (TET), chloramphenicol, azithromycin (AZI), erythromycin (ERY), streptomycin (STR), gentamicin, and telithromycin. To investigate C. jejuni genotypes, pulsed-field gel electrophoresis (PFGE) profile analysis was performed. RESULTS: The isolation rate of C. jejuni was 2.0% for the last 4 years and increased annually. Antimicrobial resistance rates of C. jejuni were shown to be in the order of NAL (90.9%), CIP (89.4%), TET (13.6%), AZI (3.0%), ERY (3.0%), and STR (1.5%). The proportion of multidrug-resistance was 18.2%, and they commonly contained quinolones (CIP-NAL). Analysis of PFGE patterns of SmaI-restricted DNA of C. jejuni isolates showed 17 clusters; cluster 11 was the major genotype pattern. CONCLUSION: This study will provide useful data for the proper use of antimicrobials and the management of resistant C. jejuni. Also it will help to provide data for the epidemiological investigation of foodborne diseases caused by C. jejuni, which is expected to increase in the future.
Azithromycin ; Busan ; Campylobacter jejuni ; Campylobacter ; Chloramphenicol ; Ciprofloxacin ; Diarrhea ; Disease Outbreaks ; DNA ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin ; Foodborne Diseases ; Gastroenteritis ; Genotype ; Gentamicins ; Humans ; Incidence ; Korea ; Methods ; Nalidixic Acid ; Quinolones ; Streptomycin ; Tetracycline

BACKGROUND: Salmonella is an important pathogen that causes gastroenteritis and sepsis in humans. Recently, changes in serotype prevalence and an increase in antimicrobial resistance have been reported. This study investigated the distribution of Salmonella serotypes and determined the antimicrobial susceptibility of various strains. METHODS: We collected 113 Salmonella isolates other than Salmonella serotype Typhi from 18 university hospitals in 2015. The serotypes were identified by Salmonella antisera O and H according to the Kauffman White scheme. Antimicrobial susceptibility tests for 12 antibiotics were performed using the disk diffusion method or E-test. RESULTS: We identified 22 serotypes. Serotype group B (44.2%) was the most common, followed by groups C (34.5%) and D (21.2%). Salmonella I 4,[5],12:i:- (23.0%), S. Enteritidis (16.8%), and S. Typhimurium (12.4%) were the most common species. Resistance rates for ampicillin, chloramphenicol, ceftriaxone, and trimethoprim/sulfamethoxazole were 46.9%, 18.5%, 8.8%, and 5.3%, respectively. The intermediate resistance rate to ciprofloxacin was 29.2%. Six isolates were extended-spectrum β-lactamase (ESBL) producers, including 5 bla(CTX-M-15) and 1 bla(CTX-M-55). CONCLUSION: There have been changes in the serotype prevalence and antimicrobial resistance of Salmonella in Korea, with a high prevalence of CTX-M 15-positive strains. Continuous monitoring of Salmonella serotypes and antimicrobial resistance is warranted.
Ampicillin ; Anti-Bacterial Agents ; Ceftriaxone ; Chloramphenicol ; Ciprofloxacin ; Diffusion ; Gastroenteritis ; Hospitals, University ; Humans ; Immune Sera ; Korea ; Methods ; Prevalence ; Salmonella ; Sepsis ; Serogroup ; Serotyping

Hematopoiesis has a pivotal role in the maintenance of body homeostasis. Ironically, several hematological disorder caused by chemicals, drugs, and other environmental factors lead to severe bone marrow failure. Current treatments like stem cell transplantation and immunosuppression remain ineffective to ameliorate this diseases. Therefore, a newtreatment to overcome this entity is necessary, one of them by promoting the usage of medicinal plants. Thus, this study aimed to evaluate the hematopoiesis potency of S. javanica berries and leaves extracts in chloramphenicol (CMP)-induced aplastic anemia mice model. In this present study, several types of blood progenitor cell such as TER-119⁺VLA-4⁺ erythrocytes lineage, Gr-1⁺ granulocytes, and B220⁺ B-cell progenitor cells were evaluated by flow cytometry analysis. Accordingly, we revealed that S. javanica berries and leaves extracts significantly promoted TER-119⁺VLA-4⁺ erythrocytes lineage and Gr-1⁺ granulocytes after exposed by CMP. Thus, these results suggested that S. javanica berries and leaves extracts might have hematopoiesis activity in CMP-induced aplastic anemia mice model.
Anemia, Aplastic ; Animals ; B-Lymphocytes ; Bone Marrow ; Chloramphenicol ; Erythrocytes ; Flow Cytometry ; Fruit ; Granulocytes ; Hematopoiesis ; Homeostasis ; Immunosuppression ; Iron ; Mice ; Plants, Medicinal ; Sambucus ; Stem Cell Transplantation ; Stem Cells

Anthrax, caused by Bacillus anthracis, is a non-contagious infectious disease that affects a wide range of animal species (primarily ruminants) including humans. Due to the often-fatal outcome in humans, quick administration of definitely effective antimicrobials is crucial either as prophylaxis or as a clinical case therapy. In this study, 110 B. anthracis strains, temporally, geographically, and genetically different, isolated during anthrax outbreaks in Italy from 1984 to 2017, were screened using a broth microdilution method to determine their susceptibility to 16 clinically relevant antimicrobial agents. The strains were isolated from various matrices (human, animal, and environmental samples) and were representative of thirty distinct genotypes previously identified by 15-loci multiple-locus variable-number of tandem repeats analysis. The antimicrobials tested were gentamicin, ceftriaxone, streptomycin, penicillin G, clindamycin, chloramphenicol, vancomycin, linezolid, cefotaxime, tetracycline, erythromycin, rifampin, amoxicillin, ciprofloxacin, doxycycline, and trimethoprim. All isolates were susceptible to most of the tested antimicrobials, with the exception of trimethoprim for which all of them showed high minimal inhibitory concentration values. An intermediate level of susceptibility was recorded for ceftriaxone and cefotaxime. Although the Centers for Disease Control and Prevention recommend the use of doxycycline, ciprofloxacin, penicillin G, and amoxicillin for treatment of human cases and for post-exposure prophylaxis to anthrax spores, this study shows a high degree of in vitro susceptibility of B. anthracis to many other antimicrobials, suggesting the possibility of an alternative choice for prophylaxis and therapy.
Amoxicillin ; Animals ; Anthrax ; Anti-Infective Agents ; Bacillus anthracis ; Bacillus ; Cefotaxime ; Ceftriaxone ; Centers for Disease Control and Prevention (U.S.) ; Chloramphenicol ; Ciprofloxacin ; Clindamycin ; Communicable Diseases ; Disease Outbreaks ; Doxycycline ; Erythromycin ; Genotype ; Gentamicins ; Humans ; In Vitro Techniques ; Italy ; Linezolid ; Methods ; Microbial Sensitivity Tests ; Penicillin G ; Post-Exposure Prophylaxis ; Rifampin ; Spores ; Streptomycin ; Tandem Repeat Sequences ; Tetracycline ; Trimethoprim ; Vancomycin

Silk fibroin/xanthan composite was investigated as a suitable biomedical material for controlled drug delivery, and blending ratios of silk fibroin and xanthan were optimized by response surface methodology (RSM) and artificial neural network (ANN) approach. A non-linear ANN model was developed to predict the effect of blending ratios, percentage swelling and porosity of composite material on cumulative percentage release. The efficiency of RSM was assessed against ANN and it was found that ANN is better in optimizing and modeling studies for the fabrication of the composite material. In-vitro release studies of the loaded drug chloramphenicol showed that the optimum composite scaffold was able to minimize burst release of drug and was followed by controlled release for 5 days. Mechanistic study of release revealed that the drug release process is diffusion controlled. Moreover, during tissue engineering application, investigation of release pattern of incorporated bioactive agent is beneficial to predict, control and monitor cellular response of growing tissues. This work also presented a novel insight into usage of various drug release model to predict material properties. Based on the goodness of fit of the model, Korsmeyer–Peppas was found to agree well with experimental drug release profile, which indicated that the fabricated material has swellable nature. The chloramphenicol (CHL) loaded scaffold showed better efficacy against gram positive and gram negative bacteria. CHL loaded SFX55 (50:50) scaffold shows promising biocomposite for drug delivery and tissue engineering applications.
Chloramphenicol ; Diffusion ; Drug Liberation ; Fibroins ; Gram-Negative Bacteria ; Porosity ; Silk ; Tissue Engineering

Clostridium perfringens causes diarrhea and other diseases in animals and humans. We investigated the prevalence, toxin gene profiles, and antibiotic resistance of C. perfringens isolated from diarrheic dogs (DD) and non-diarrheic dogs (ND) in two animal hospitals in Seoul, Korea. Fecal samples were collected from clinically DD (n = 49) and ND (n = 34). C. perfringens was isolated from 31 of 49 DD (63.3%) and 21 of 34 ND dogs (61.8%). All C. perfringens strains were positive for the α toxin gene, but not for the β, ε, or ι toxin genes; therefore, all strains were identified as type A C. perfringens. All isolates were cpe-negative, whereas the β2 toxin gene was identified in 83.9% and 61.9% of isolates from DD and ND, respectively. Most isolates were susceptible to ampicillin (94%), chloramphenicol (92%), metronidazole (100%), moxifloxacin (96%), and imipenem (100%). However, 25.0% and 21.2% of isolates were resistant to tetracycline and clindamycin, respectively. Molecular subtyping of the isolated strains was performed by using pulsed-field gel electrophoresis. Fifty-two isolates were classified into 48 pulsotypes based on more than 90% similarity of banding patterns. No notable differences were observed among the isolates from DD and ND.
Ampicillin ; Animals ; Bacterial Toxins ; Chloramphenicol ; Clindamycin ; Clostridium perfringens ; Clostridium ; Diarrhea ; Dogs ; Drug Resistance ; Drug Resistance, Microbial ; Electrophoresis, Gel, Pulsed-Field ; Hospitals, Animal ; Humans ; Imipenem ; Korea ; Metronidazole ; Prevalence ; Seoul ; Tetracycline

OBJECTIVES: The aim of this study was to determine the prevalence of asymptomatic carriers of group A β-hemolytic streptococci (GAS) in children living in a rural community and to investigate the association between episodes of acute pharyngitis and carrier status. METHODS: Throat swabs were collected from September to November 2013 among children 5-13 years of age from a rural community (Maria Ignacia-Vela, Argentina). The phenotypic characterization of isolates was performed by conventional tests. Antimicrobial susceptibility was assayed for penicillin, tetracycline, chloramphenicol, erythromycin, and clindamycin (disk diffusion). The minimum inhibitory concentration was determined for penicillin, cefotaxime, tetracycline, and erythromycin. RESULTS: The carriage of β-hemolytic streptococci was detected in 18.1% of participants, with Streptococcus pyogenes in 18 participants followed by S. dysgalactiae ssp. equisimilis in 5. The highest proportion of GAS was found in 8 to 10-year-old children. No significant association between the number of episodes of acute pharyngitis suffered in the last year and the carrier state was detected (p>0.05). Tetracycline resistance (55.5%) and macrolide-resistant phenotypes (11.1%) were observed. Resistance to penicillin, cefotaxime, or chloramphenicol was not expressed in any streptococcal isolate. CONCLUSIONS: The present study demonstrated significant throat carriage of GAS and the presence of group C streptococci (S. dysgalactiae ssp. equisimilis) in an Argentinian rural population. These results point out the need for continuous surveillance of GAS and non-GAS carriage as well as of antimicrobial resistance in highly susceptible populations, such as school-aged rural children. An extended surveillance program including school-aged children from different cities should be considered to estimate the prevalence of GAS carriage in Argentina.
Argentina* ; Carrier State ; Cefotaxime ; Child* ; Chloramphenicol ; Clindamycin ; Erythromycin ; Humans ; Microbial Sensitivity Tests ; Penicillins ; Pharyngitis ; Pharynx* ; Phenotype ; Prevalence ; Rural Population ; Streptococcus pyogenes* ; Streptococcus* ; Tetracycline ; Tetracycline Resistance

PURPOSE: Chloramphenicol and tetracycline are not recommended for treating scrub typhus in pediatric patients because of potential side effects, such as aplastic anemia or tooth discoloration. While clarithromycin has recently been used in adults, few reports have been published on its effects in pediatric patients. We report the clinical profiles of pediatric scrub typhus and the effects of clarithromycin on scrub typhus in children. METHODS: We retrospectively analyzed medical records of 56 children with scrub typhus who were admitted between 2004 and 2013 to Chonbuk National University Hospital, Jeonju, Korea. Cases were divided into 3 groups based on thetreatment drug (chloramphenicol, azithromycin, and clarithromycin). We compared their clinical manifestations and laboratory findings. RESULTS: All patients exhibited fever and rash. Other common clinical manifestations were eschars (66%), lymphadenopathy (48%), upper respiratory symptoms (42%), abdominal pain (32%), and hepatosplenomegaly (14%). Elevated levels of C-reactive protein, erythrocyte sedimentation rates, aspartate transaminase, and alanine transaminase were detected in 95%, 96%, 84%, and 77% of patients, respectively. Additionally, decreased platelet and white blood cell levels were observed in 43% and 36% of patients, respectively. There were no statistical differences between the treatment groups in mean age (P=0.114) or sex (P=0.507). However, time to defervescence after the treatments differed significantly, being the shortest in the clarithromycin group (P=0.019). All patients recovered without complications related to the disease or drugs. CONCLUSION: Clarithromycin was as effective as chloramphenicol and azithromycin in pediatric scrub typhus patients and may be used as a first-line treatment drug.
Abdominal Pain ; Adult ; Alanine Transaminase ; Anemia, Aplastic ; Aspartate Aminotransferases ; Azithromycin* ; Blood Platelets ; Blood Sedimentation ; C-Reactive Protein ; Child* ; Chloramphenicol* ; Clarithromycin* ; Exanthema ; Fever ; Humans ; Jeollabuk-do ; Korea ; Leukocytes ; Lymphatic Diseases ; Medical Records ; Retrospective Studies ; Scrub Typhus* ; Tetracycline ; Tooth Discoloration