To investigate genetic relatedness and antibiotic resistance of Klebsiella pneumoniae from retail meat samples, clinical source samples, and hospital environmental samples in Wuhan, China.
...Hypermucoviscosity and biofilm formation of K. pneumoniae were assessed by string test and crystal violet staining. MICs of 18 antimicrobials were determined by broth microdilution. PCR detected 14 antibiotic resistance genes. Genetic relatedness and clonal dissemination were analyzed by PFGE.
Among 5,730 samples, 46 were tested positive for K pneumoniae, with higher rates observed in meat (23.4%) than in clinical samples (0.6%) and hospital environmental samples (8.0%). Meat-derived isolates showed high resistance to tetracycline (36.4%, 4/11), sulfonamide (27.3%, 3/11), and gentamicin (27.3%, 3/11), whereas clinical isolates exhibited significant resistance to ampicillin-sulbactam (32.3%, 10/31). Multidrug resistance was observed in 17.4% (8/46) of the isolates, particularly in hospital environmental samples (3/4). Biofilm production was observed in 88.1% (37/42) of K pneumoniae. Pulsed-field gel electrophoresis analysis revealed patient-to-patient K pneumoniae transmission, transmission between patients and hospital environment, as well as cross-contamination between markets.
The findings underscore the importance of comprehensive surveillance, infection control, and judicious antibiotic use in mitigating the impact of K pneumoniae on public health, especially in the food chain and health care settings.
•Detection of Klebsiella pneumoniae in pediatric patients, clinical settings, and foodstuff.•Virulence phenotypes and biofilm formation of K pneumoniae from different sources.•Antibiotic resistance and resistance genes of K pneumoniae from different sources.•Homology analysis indicates its transmission between different sources.
DNA markers are used as a size reference and sample loading control during gel electrophoresis. Most markers are designed for conventional gel electrophoresis to separate DNA smaller than 20 kb. For ...larger molecules, pulsed-field gel electrophoresis (PFGE) marker is required. Limited PFGE markers are available because large DNA are prone to nicking and degradation, causing smeary bands. Here, we developed a robust marker based on bacterial artificial chromosomes (BACs) with bands up to 184 kb. This marker could consistently confer intense and distinct bands for accurate gel analysis in molecular biology studies, laboratory validations or clinical diagnosis.
Display omitted
•PFGE marker is prone to DNA degradation, which gives smeary banding patterns, causing difficulties in gel analysis.•We have developed a set of low-range PFGE markers based on restriction endonuclease fragments of bacterial artificial chromosomes.•Instead of giving only single banding pattern, this method offers almost endless possible combinations of customizable bands up to 184 kb.•It gives distinct band distribution and accurate quantification of nucleic acid compared to traditional markers.
Enterobacteriaceae species have caused foodborne illnesses through consumption of a variety of foods, including infant foods. A total of 915 samples representing 4 types of samples, were collected ...from 7 powdered infant formula factories in Heilongjiang Province, China. All samples were processed for enumeration of Enterobacteriaceae and isolation of Cronobacter sakazakii, which were detected using the ISO enrichment procedure and a chromogenic medium. Multi-locus sequence typing (MLST), and pulsed field gel electrophoresis (PFGE) were applied to characterize the C. sakazakii isolates to trace back the original source of contamination. Samples were considered Enterobacteriaceae positive at 10 CFU/g in powdered samples, 1 CFU/mL in water samples, and 10 CFU/100 cm2 or larger surface area. Enterobacteriaceae positive rate were 0/35 water samples associated with production, 11/56 raw materials, 147/761 environmental samples and 3/63 finished products respectively. C. sakazakii strains were isolated from 7.0% of environmental samples followed by 1.6% of the finished products. A total of 20 C. sakazakii isolates were recovered in Factory 4, 1 strain derived from a final product and 19 strains recovered from the environment representing 4 MLST sequence types and 10 PFGE pulse types. Most environmental sites positive for C. sakazakii had higher counts of Enterobacteriaceae, except for 11 sites where Enterobacteriaceae did not reach minimal levels for reporting a positive sample. The present study, provides insight to the correlation between the prevalence of Enterobacteriaceae and contamination of C. sakazakii in powdered infant formula factories; there is no one-to-one relation between number of Enterobacteriaceae and C. sakazakii. Identifying environmental sites positive for C. sakazakii and/or Enterobacteriaceae will aid in development of appropriate corrective measures to improve environmental hygiene and enhance safety of powdered infant formula.
Aim: This study aimed to determine the susceptibility of carbapenem-resistant Gr (-) bacilli isolated from various clinical infections to various antibiotics and identify genes causing carbapenem ...resistance and their clonal relationships to elucidate the distribution of resistance in community and/or hospital-acquired strains.
Material and methods: In this study, antibiotic susceptibilities of 450 carbapenem-resistant Gr (-) bacilli isolated from clinical specimens at Cukurova University, Faculty of Medicine, Balcali Hospital, were investigated using phenotypic methods. The presence of carbapenems and β-lactamase genes were searched using polymerase chain reaction (PCR) and sequence analysis methods. Pulsed-field gel electrophoresis (PFGE) method was used to evaluate the phylogenetic relationship of the isolates.
Results: Based on the results, it was determined that 99.23% of the strains had gained resistance to meropenem, whereas 5.38% had developed resistance to colistin. The most dominant carbapenems genes in all isolates were OXA-51, OXA-23-like and OXA-24-like.
Conclusion: It was observed that the only antibiotic that could be used safely in carbapenem-resistant Gr (-) bacilli infections was colistin. In addition, when the clonal relationship of the strains was examined, it was found that the clones considered to be closely related persisted, and these clones settled in different clinics of our hospital.
Display omitted
•Ceratocystis fimbriata isolates exhibit variability in chromosome number and size.•Variability in both large and small chromosomes was observed among the Brazilian ...isolates.•REMAP-based cluster analysis indicates C. fimbriata exhibits retrotransposon-associated genetic variability.•Repetitive elements may potentially be involved in C. fimbriata chromosomal rearrangements.
Ceratocystis fimbriata is an important pathogen that causes wilt in several plant species. Despite the importance of this pathogen, knowledge about its karyotypic polymorphism and genomic architecture is limited. The main objective of this study was to investigate the karyotype of isolates of the C. fimbriata species complex from different host plants and geographical origins in Brazil. First, the identity of the isolates was confirmed conducting multilocus sequence analysis (MLSA) phylogeny using β-tubulin (TUBB), translation elongation factor 1α (TEF-1α) and mating-type (MAT1 and MAT2) gene sequences. To investigate the chromosomal polymorphism, two conditions of pulsed-field gel electrophoresis (PFGE) were used and the karyotypes of the isolates obtained. The retrotransposon-microsatellite amplified polymorphism (REMAP) molecular marker was utilized to assess the genetic variability among isolates. In the MLSA utilizing the concatenated gene sequences, Ceratocystis cacaofunesta and C. fimbriata formed separate clades, but considerable variation among C. fimbriata isolates was observed. Polymorphism in chromosome number and size was found, indicating the existence of genomic differences among isolates and occurrence of chromosomal rearrangements in the species complex. The number of chromosomes varied from seven to nine and the estimated minimum chromosome sizes were estimated to be between 2.7 and 6.0 Mbp. Small polymorphic chromosomes ranging from 1.2 to 1.8 Mbp were observed in all isolates, raising the hypothesis that they could be supernumerary chromosomes. REMAP analysis revealed a high genetic variability and that isolates from the same host tend to group together in a same cluster. Our results bring new insights into the chromosomal diversity and genome organization of the C. fimbriata complex.
Neonatal sepsis is a nuisance to clinicians and medical microbiologists, particularly those cases caused by
. Thus, we aimed at investigating the profile and mechanisms of antibiotic resistance and ...the clonal relationships between
isolated from neonates at the largest tertiary care hospital's neonatal intensive care units (NICUs) in Minia, Egypt.
This study comprised 156 neonates diagnosed with culture-proven sepsis from February 2019 to September 2019, at a major NICU of Minia City. All
isolates were collected and characterized by antimicrobial profile, resistance genotype, and pulsed-field gel electrophoresis typing.
Twenty-four
isolates (15.3%) were collected out of the 156 sepsis diagnosed neonates. These samples showed extensive drug resistance (XDR) to most of the tested antimicrobials, except fluoroquinolones. All the
isolates possessed
and
carbapenemase genes, while
gene was detected in 95.8%. Considering extended-spectrum β-lactamases genes,
was found in all the isolates and
gene in 75% of them. The plasmid-mediated quinolone resistance gene
S, was predominantly found among our isolates in comparison to
B or
A. A moderate degree of clonal relatedness was observed between the isolates.
To the best of our knowledge, this the first report of an alarming occurrence of XDR among
isolates recovered from neonatal sepsis in Egypt. Our data necessitate proper antimicrobial stewardship as the choices will be very limited.
Staphylococcus aureus causes mastitis in dairy cows, lambs, goats, and skin disorders in pigs and other animals. S. aureus causes localized purulent infections that affect soft tissues, bones, and ...other organs in humans. Using restriction patterns, the researchers want to isolate and identify methicillin-resistant Staphylococcus aureus (MRSA) strains from cattle and humans. They also hope to assess their genetic relatedness by comparing the mecA1 and mecA2 gene sequence discrepancies. Animals (223 strains) and people have been used to acquire S. aureus strains for study (83). The E-test was used to assess whether or not the bacteria were resistant to methicillin. The mecA1 and mecA2 genes were identified by using pulsed-field gel electrophoresis (PFGE) to analyze DNA restriction patterns. The results were shown. S. aureus strains from animals and men were resistant to methicillin in 32 (14.34 %) and 53 (63.8 %), respectively. PFGE was used to determine the differences between human and veterinary pathology strains. Two strains of bacteria collected from animals were discovered to be identical; nevertheless, microorganisms recovered from humans were found to be significantly similar to the bacteria recovered from animals. Both human and veterinary pathology were implicated in the development of methicillin resistance. The MRSA strains found in humans were much more significant than those found in animals. The strains recovered from animals exhibited a high degree of genetic heterogeneity. Still, the enormous number of indistinguishable bacteria in humans leads one to believe that a dominant clone is present. When it comes to the molecular characterization of MRSA isolates, PFGE might be regarded as the gold standard.
Keywords. Animals, Human, MRSA, PFGE, Staphylococcus, mecA genes
This study aimed to investigate the prevalence, serotype distribution, and antibiotic resistance, and to characterize the extended spectrum β-lactamases (ESBLs) producing
isolates from chicken and ...pork meats from retail markets in Guangdong province, China. A total of 903 retail meat samples (475 chicken and 428 pork meats) were obtained from six cities (Guangzhou, Shenzhen, Heyuan, Shaoguan, Foshan, and Yunfu) of Guangdong province between May 2016 and April 2017. High levels of
contamination were detected in chicken (302/475, 63.6%) and pork (313/428, 73.1%). Thirty-eight serotypes were identified in 615 detected
, and the serotypes varied greatly between chicken and pork samples. Agona (55/302, 18.2%), Corvallis (45/302, 14.9%), Kentucky (38/302, 12.6%), Mbandaka (32/302, 10.6%) was the dominant serotypes in chicken samples. However, Typhimurium (78/313, 24.9%), Rissen (67/313, 24.1%), Derby (66/313, 21.1%), and London (48, 15.3%) were the most common in pork samples. High rates of antibiotic resistance were found to sulfisoxazole (468/615, 76.1%), tetracycline (463/615, 75.3%), ampicillin (295/615, 48.0%), and ofloxacin (275/615, 44.7%). Notably, antimicrobial susceptibility tests identified resistance to polymyxin B (12/615, 2.0%) and imipenem (3/615, 0.5%). Multidrug-resistance (MDR) was detected in
isolated from chicken (245/302, 81.1%) and pork (229/313, 73.2%). The resistance rate of different
serotypes varied widely. Especially, isolates such as Typhimurium, Agona,
orvallis and Kentucky exhibited highly resistance to antibiotics. The MDR rate of
isolates from chicken was significantly higher than that from pork isolates (
< 0.05). Twenty-one
isolates were identified as ESBLs-producing, covering six
serotypes and displaying different pulse field gel electrophoresis (PFGE) genotypes.
was the dominant ESBLs gene (9/21, 42.9%), followed by
(5/21, 23.8%). This study indicated that
was widespread in chicken and pork from retail markets in Guangdong province and the isolates showed high multidrug-resistance, especially the known multidrug-resistant
serotypes. Therefore, it is important to focus on
serotypes and strengthen the long-term monitoring of MDR
serotypes in animal-derived foods.
PDF
