Epidemiological Investigation of Salmonella enterica Isolates in Children with Diarrhea in Chengdu, China

Background: Children with the immature intestinal immune system are prone to Salmonella infection through the fecal-oral route causing diarrhea. Non-typhoid Salmonella (NTS) is difficult to treat and eliminate due to its zoonosis. Salmonella typhi, including typhoid and paratyphoidA, B, and C, only infect humans and cause invasive infectious diseases. Salmonella typhi infection is serious and requires antibiotic treatment. The bacterial resistance caused by conventional antibacterial drugs brings great difficulties to treatment. Objectives: This study aimed to investigate the epidemiology of S. enterica in children with diarrhea in Chengdu, China. Methods: Fresh stool specimens or rectal swabs from 6656 children aged 1 day to 17 years with diarrhea were collected, cultured, identified, and tested for antimicrobial susceptibility. Analytical Profile index 20E was used for biochemical identification, and the Kirby-Bauer method was used for the bacterial sensitivity test. The whole process was conducted in accordance with the fourth edition of the National Clinical Examination procedures, and the drug sensitivity test was conducted in accordance with the Clinical and Laboratory Standards Institute 2020 guidelines. Results: A total of 649 Salmonella strains were isolated from 6656 children with suspected Salmonella infection, among which the isolation rates of NTS and S. typhi were 8.92% and 0.83%, respectively. The infection rate of S. typhimurium was the highest every year (74.88%). Salmonella infections are on the rise, especially typhimurium, Dublin, Typhi, and London. Paratyphi is unstable, presenting a phenomenon of transition and replacement (the male to female ratio:1.12:1). The infection rate was the lowest within 1 day and 6 months (P < 0.05). Salmonella mainly infected children under 3 years of age, and the positive rate was reported as 88.29%. Within June-September, the infection rate of Salmonella was the highest, with a positive rate of 72.73%. The isolated 649 Salmonella strains had good susceptibility to cefotaxime and ciprofloxacin (87.7% and 79.2%, respectively), almost no susceptibility to ampicillin, and a drug resistance rate of 92.9%. Conclusions: typhoid and paratyphoid vaccines should be considered together, and vaccines should focus on children under 3 years of age. Antibiotics should be rationally selected according to the drug sensitivity test and disease condition.

Changes of antibiotic resistance over time among Escherichia coli peritonitis in Southern China

Escherichia coli ( E. coli) is the main cause of Gram-negative bacterial peritonitis among peritoneal dialysis patients. According to the 2016 update of the International Society for Peritoneal Dialysis Peritonitis Recommendations, drug susceptibilities of specific organisms should be regularly monitored. The aim of this study was to examine the evolution of antimicrobial resistance of E. coli peritonitis from 2006 to 2018. Two hundred and fifty-three episodes of E. coli peritonitis were enrolled in our study, corresponding to a rate of 0.024 episodes per patient-year. According to drug sensitivity test results, isolates were most sensitive to carbapenems, followed by cefmetazole, piperacillin/tazobactam, cefotetan and amikacin, with an overall rate of more than 90% in both cohorts. Cefazolin and ciprofloxacin resistance increased significantly from 2006–2011 to 2012–2018. Conversely, cefepime and ceftazidime resistance decreased significantly. The extended-spectrum β-lactamase (ESBL) rate fluctuated from 34.7% in 2006–2011 to 46.8% in 2012–2018. Compared with the ESBL-negative strains, ESBL-producing E. coli were more likely be resistant to ampicillin, ampicillin/sulbactam, cephalosporins, quinolones, aminoglycosides, furadantin and sulfamethoxazole and accounted for over 50% of the drug resistance. In the correlation analysis, E. coli displayed significantly increased resistance to cefazolin and ciprofloxacin, a finding correlated with ESBL production ( r = 0.883 and 0.276 respectively, p < 0.001 and p = 0.003). In conclusion, the rate of E. coli peritonitis declined stably in recent years, but the resistance to antimicrobial was high.

Analysis of the application of a gene chip method for detecting Mycobacterium tuberculosis drug resistance in clinical specimens: a retrospective study

Most Mycobacterium tuberculosis (Mtb) resistant to rifampicin (RIF) has mutations in the rpoB gene, while most Mtb resistant to isoniazid (INH) has mutations in the katG gene or inhA promoter. We used gene chip technology to detect mutations in these genes to determine the resistance of Mtb to RIF and INH. A total of 4148 clinical specimens with sputum smear positivity for acid-fast bacilli (AFB) were detected. Then, taking the results of the drug sensitivity test (DST) as the reference standard, the detection efficiency of sputum samples from different grades of positive smears was compared in detail. We found that the sensitivity of the gene chip method for detecting sputum samples with a grade ≥ AFB 2 + was higher than that of sputum samples with a grade ≤ AFB 1 + (P < 0.05). When the grade of the sample was ≤ AFB 1 +, the sensitivity of the gene chip method was 72.6% for RIF, 67.3% for INH, and 60.0% for MDR-TB. When the grade of the sample was ≥ AFB 2 +, the sensitivity of the gene chip method was 84.5% for RIF, 78.2% for INH, and 73.9% for MDR-TB. The results show that gene chip technology can be directly used to diagnose drug-resistant tuberculosis in clinical specimens, and the diagnostic efficiency for the detection of sputum specimens with a grade ≥ AFB 2 + is better than that of other sputum specimens.

Intratumoral gene expression of dihydrofolate reductase and folylpoly-c-glutamate synthetase affects the sensitivity to 5-fluorouracil in non-small cell lung cancer

Background Various factors related to the sensitivity of non-small cell lung carcinoma (NSCLC) to 5-fluorouracil (5-FU) have been reported, and some of them have been clinically applied. In this single-institutional prospective analysis, the mRNA expression level of five folic acid-associated enzymes was evaluated in surgical specimens of NSCLC. We investigated the correlation between the antitumor effect of 5-FU in NSCLC using an anticancer drug sensitivity test and the gene expression levels of five enzymes. Materials and methods Forty patients who underwent surgery for NSCLC were enrolled, and the antitumor effect was measured using an in vitro anticancer drug sensitivity test (histoculture drug response assay) using freshly resected specimens. In the same sample, the mRNA expression levels of five enzymes involved in the sensitivity to 5-FU were measured in the tumor using real-time PCR. The expression levels and the result of the sensitivity test were compared. Results No correlation was found between dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT), or DPD/OPRT expression and the antitumor effects of 5-FU. On the other hand, a correlation was found between thymidylate synthase (TS), folylpoly-c-glutamate synthetase (FPGS), and dihydrofolate reductase (DHFR) expression and 5-FU sensitivity. Conclusion Expression of FPGS and DHFR may be useful for predicting the efficacy of 5-FU-based chemotherapy for NSCLC.

Clinical characteristics and drug sensitivity analysis of bloodstream infection caused by Klebsiella pneumoniae in the north of Henan province

Objectives To analyze clinical characteristics of bloodstream infection caused by Klebsiella pneumoniae and antibiotic resistance of Klebsiella pneumoniae in the north of Henan province, provide the basis for rational selection of antimicrobial drugs. Methods Klebsiella pneumoniae was isolated from 195 patients with bloodstream infection caused by Klebsiella pneumoniae in 2017 in the north of Henan Province, Phoenix100 blood culture and identification system were used for bacterial identification and drug sensitivity test was used for antibiotic resistance detection, and WHONET 5.6 software was used for data analysis of antibiotic resistance and antibiotic sensitivity; the medical history of patients, antibiotic use and laboratory examination results of 195 cases of patients with bloodstream infection caused by Klebsiella pneumoniae were also retrospectively analyzed. Results The patients with bloodstream infection caused by Klebsiella pneumoniae were mainly distributed in ICU, surgical department and Internal medicine department. There were 110 patients with bloodstream infection caused by Klebsiella pneumoniae accompanied with underlying diseases, accounting for 56.41% in 195 patients with bloodstream infection caused by Klebsiella pneumoniae, and 87 (87/110, 77.3%) patients accompanied with hypertension and diabetes. Drug sensitivity test showed that in 195 patients with bloodstream infection caused by Klebsiella pneumoniae, the top three antibiotics of the drug resistance rate of Klebsiella pneumoniae were cefazolin (74%), amoxicillin/clavulanic acid (70.1%), ampicillin /sulbactam (68.5%); the lower three antibiotics of drug resistance rate were imipenem (52%), cefepime (53%) and amikacin (33%); there were 81 strains of Klebsiella pneumoniae produced ESBLs, accounting for 41.53% in 195 strains of Klebsiella pneumoniae. The drug resistance rate of ESBLs positive strains was significantly higher than that of ESBL negative strains. It should be pointed out that the resistance of ESBLs positive strains of Klebsiella pneumoniae to cefazole reached 100%, followed by gentamicin (71.4%), ciprofloxacin (70.4%) and levofloxacin (69.1%); The resistance of ESBLs negative strains to cefazole was 18.2%, followed by gentamicin (3.5%), ciprofloxacin (3.0%) and levofloxacin (19.3%). Conclusions The number of total bacteria isolated from departments with large number of patients is relatively large, and the number of pneumonia patients caused by Klebsiella is also increased; ESBLs positive strains in this hospital are still the main reasons for the drug resistance of Klebsiella pneumoniae, reducing the antibiotics use of cefazol, gentamycin, ciprofloxacin and levofloxacin can effectively reduce the resistance of Klebsiella pneumoniae in the hospital. At the same time, we should pay attention to some contraindications for treating hypertension, diabetes drugs and antibiotics; the clinical staff should pay attention to the timely blood culture test, rational drug use can reduce the emergence of drug-resistant strains and prevent the outbreak of nosocomial infection.

A Methylene Blue Assisted Electrochemical Sensor for Determination of Drug Resistance of Escherichia coli

Due to the abuse of antibiotics in clinical, animal husbandry, and aquaculture, drug-resistant pathogens are produced, which poses a great threat to human and the public health. At present, a rapid and effective drug sensitivity test method is urgently needed to effectively control the spread of drug-resistant bacteria. Using methylene blue as a redox probe, the electrochemical signals of methylene blue in drug-resistant Escherichia coli strains were analyzed by a CV method. Graphene ink has been used for enhancing the electrochemical signal. Compared with the results of the traditional drug sensitivity test, we proposed a rapid electrochemical drug sensitivity test method which can effectively identify the drug sensitivity of Escherichia coli. The sensitivity of four E. coli isolates to ciprofloxacin, gentamicin, and ampicillin was tested by an electrochemical drug sensitivity test. The respiratory activity value %RA was used as an indicator of bacterial resistance by electrochemical method.

Disseminated nocardiosis caused by Nocardia vulneris in a macroglobulinemia patient

Headings Background : This is a case of a human disseminated nocardiosis caused by Nocardia vulneris which made the patient presenting with fever, cough, shortness of breath, muscle pain and multiple tubercle. Methods: Bacterial culture the blood, sputum, lung rinses and scalp pus samples of the patient, Nocardia vulneris was isolated and identified using the 16s ribosomal RNA gene sequence sequence data. and determine the sensitivity of the isolated bacteria to antibiotics and analysis of the strain's antibiotic treatment. Results: The isolated was identified as Nocardia brasiliensis, which was resistant to ciprofloxacin, but susceptible to amikacin, gentamicin, tobramycin, linezolid, trimethoprim-sulfamethoxazole, amoxicillin/clavulanic, moxifloxacin, ceftriaxone, cefotaxim, imipenem. The patient recovered and his condition remained stable by combinations with linezolid, amikacin and trimethoprim-sulfamethoxazole. Conclusions: This is the first case report of disseminated nocardiosis caused by Nocardia vulneris, and the current case was treated successfully with linezolid, amikacin and trimethoprim-sulfamethoxazole. Clinicians should be aware of its diagnostic, and the MIC value of the drug sensitivity test should be concerned when there is a wide choice of medicines, for the disseminated cases which are diagnosed definitely should be treated with at least 12 months of antimicrobial therapy, bacteriological examination and antimicrobial susceptibility testing should be performed repeatedly.

Identifying Infliximab- (IFX-) Responsive Blood Signatures for the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a severe chronic pathogenic inflammatory abnormality that damages small joints. Comprehensive diagnosis and treatment procedures for RA have been established because of its severe symptoms and relatively high morbidity. Medication and surgery are the two major therapeutic approaches. Infliximab (IFX) is a novel biological agent applied for the treatment of RA. IFX improves physical functions and benefits the achievement of clinical remission even under discontinuous medication. However, not all patients react to IFX, and distinguishing IFX-sensitive and IFX-resistant patients is quite difficult. Thus, how to predict the therapeutic effects of IFX on patients with RA is one of the urgent translational medicine problems in the clinical treatment of RA. In this study, we present a novel computational method for the identification of the applicable and substantial blood gene signatures of IFX sensitivity by liquid biopsy, which may assist in the establishment of a clinical drug sensitivity test standard for RA and contribute to the revelation of unique IFX-associated pharmacological mechanisms.