dfrA Genes Research Articles

Antibiotic Resistance of Escherichia coli from Humans and Black Rhinoceroses in Kenya.

Upsurge of antibiotic resistance in wildlife poses unprecedented threat to wildlife conservation. Surveillance of antibiotic resistance at the human-wildlife interface is therefore needed. We evaluated differences in antibiotic resistance of Escherichia coli isolates from human and the endangered black rhinoceros in Lambwe Valley, Kenya. We used standard microbiological techniques to carry out susceptibility assays using eight antibiotics of clinical and veterinary importance. Standard PCR method was used to characterize antibiotic resistance genes. There was no difference in resistance between E. coli isolates from human and those from rhinoceros (U = 25, p = 0.462). However, higher resistance in isolates from humans was noted for cotrimoxazole (p = 0.000, OR = 0.101), ceftriaxone (p = 0.005, OR = 0.113) and amoxicillin/clavulanic acid (p = 0.017, OR = 0.258), whereas isolates from rhinoceros showed higher gentamicin resistance (p = 0.001, OR = 10.154). Multi-drug resistance phenotype was 69.0% in humans and 43.3% in rhinoceros. Isolates from both species contained blaTEM, tetA, tetB, dfrA1 and sul1 genes. Resistance profiles in the two species suggest potential for cross-transfer of resistance genes or exposure to comparable selective pressure and call for a multi-sectorial action plan on surveillance of antibiotic resistance at the human-wildlife interface. Genome-wide studies are needed to explicate the direction of transfer of genes that confer antibiotic resistance at the human-wildlife interface.

MRSA Strains in Nepalese Rhesus Macaques (Macaca mulatta) and Their Environment.

This study looked at 227 saliva samples from Rhesus macaques (Macaca mulatta) and 218 samples from the surrounding environments. From these samples, MRSA isolates were collected from Rhesus saliva samples (n = 13) and environmental samples (n = 19) near temple areas in Kathmandu, Nepal. For comparison, selected MRSA isolates (n = 5) were obtained from patients with wound infections from a Kathmandu hospital. All isolates were characterized using Abbott StaphyType® DNA microarrays. Eighteen isolates (62%) from monkeys (n = 4; 31%) and environmental samples (n = 14; 74%), were CC22-MRSA-IV. Most (n = 16) of them carried both, the PVL locus and toxic shock toxin gene (tst1), an unusual combination which is the same as in previously characterized strain from Nepalese macaques and pigs. The five human isolates also belonged to that strain type. Eight monkey MRSA isolates were CC361-MRSA-IV. One MRSA from a monkey and one from an environmental sample, were CC88-MRSA-V. Other environmental MRSA included one each, CC121-MRSA-VT, and CC772 -MRSA-V. Two were CC779-MRSA-VT, potentially a novel clone. All MRSA carried the blaZ gene. The aacA–aphD, dfrA, and erm (C) genes were very common in isolates from all sources. One macaque MRSA carried the resistance genes aphA3 and sat, neither previously identified in primate MRSA isolates. This current study suggests that humans could be a potential source of the MRSA in the macaques/environment and transmission may be linked to humans feeding the primates and/or living in close proximity to each other.

Emergence of community-acquired methicillin-resistant Staphylococcus aureus EMRSA-15 clone as the predominant cause of diabetic foot ulcer infections in Portugal.

Methicillin-resistant Staphylococcus aureus (MRSA) are often found in infected diabetic foot ulcers, in which the prevalence may reach 40%. These complications are one of the main causes of morbidity in diabetic patients. The objectives of this study were to investigate the prevalence and antimicrobial resistance of MRSA strains in infected diabetic foot ulcers and to characterize their genetic lineages. Samples collected from 42 type 2 diabetic patients, presenting infected foot ulcers, were seeded onto ORSAB plates with 2mg/L of oxacillin for MRSA isolation. Susceptibility to 14 antimicrobial agents was tested by the Kirby-Bauer disk diffusion method. The presence of resistance genes, virulence factors, and the immune evasion cluster system was studied by PCR. All isolates were characterized by MLST, accessory gene regulator (agr), spa, and staphylococcal chromosomal cassette mec (SCCmec) typing. Twenty-five MRSA strains were isolated. All isolates showed resistance to penicillin and cefoxitin. Sixteen isolates showed phenotypic resistance to erythromycin being 7 co-resistant to clindamycin. Resistance to trimethoprim-sulfamethoxazole was found in 2 isolates harboring the dfrA and dfrG genes. The IEC genes were detected in 80% of isolates, 16 of which were ascribed to IEC-type B. Isolates were assigned to 12 different spa types. The MLST analysis grouped the isolates into 7 sequence types being the majority (68%) ascribed to SCCmec type IV. In this study, there was a high prevalence of the EMRSA-15 clone presenting multiple resistances in diabetic foot ulcers making these infections complicated to treat leading to a higher morbidity and mortality in diabetic patients.

Emergence of Azithromycin Resistance Mediated by Phosphotransferase-Encoding mph(A) in Diarrheagenic Vibrio fluvialis.

The azithromycin resistance conferred by phosphotransferase is encoded in the gene mph(A). This gene has been discovered in and reported for many bacterial species. We examined the prevalence of azithromycin resistance in Vibrio fluvialis (AR-VF) isolated during 2014 to 2015 from the hospitalized acute diarrheal patients in Kolkata, India. Most of the V. fluvialis isolates are identified as the sole pathogen (54%). The prevalence of AR-VF was higher in 2015 (19 [68%]) than in 2014 (9 [32%]). Among AR-VF isolates, the azithromycin MICs ranged from 4 to >256 mg/liter. Twenty-eight of the 48 (58%) V. fluvialis isolates harbored the gene mph(A) and phenotypically resistant to azithromycin. All the AR-VF isolates remained susceptible to doxycycline. In addition to azithromycin, other antimicrobial resistance-encoding genes of AR-VF were also characterized. All the AR-VF isolates were positive for class 1 integron, and most of them (17/28) carried the dfrA1 gene cassettes. Only one isolate was positive for the ereA gene, which encodes resistance to erythomycin. The majority of the isolates were resistant to β-lactam antibiotics (blaOXA-1 [96%], blaOXA-7 [93%], and blaTEM-9 [68%]) and aminoglycoside actetyltransferase, conferring resistance to ciprofloxacin-modifying enzyme [aac(6')Ib-cr] (96%). Analyses by pulsed-field gel electrophoresis (PFGE) showed that the AR-VF isolates belonged to different genetic lineages. This is the first study to report azithromycin resistance and the presence of the mph(A) gene in V. fluvialis isolates. Circulation of AR-VF isolates with high azithromycin MICs is worrisome, since it may limit the treatment options for diarrheal infections.IMPORTANCE The progressive rise in antibiotic resistance among enteric pathogens in developing countries is becoming a big concern. India is one of the largest consumers of antibiotics, and their use is not well regulated. V. fluvialis is increasingly recognized as an emerging diarrheal pathogen of public health importance. Here we report the emergence of azithromycin resistance in V. fluvialis isolates from diarrheal patients in Kolkata, India. Azithromycin has been widely used in the treatment of various infections, both in children and in adults. Resistance to azithromycin is encoded in the gene mph(A). Emerging azithromycin resistance in V. fluvialis is a major public health challenge, and future studies should be focused on identifying ways to prevent the dissemination of this antibiotic resistance gene.

Characterization of Phenotypic and Genotypic Diversity of Stenotrophomonas maltophilia Strains Isolated From Selected Hospitals in Iran.

Stenotrophomonas maltophilia is an environmental Gram-negative bacterium that has rapidly emerged as an important nosocomial pathogen in hospitalized patients. Treatment of S. maltophilia infections is difficult due to increasing resistance to multiple antibacterial agents. The purpose of this study was to determine the phenotypic and genotypic characterization of S. maltophilia isolates recovered from patients referred to several hospitals. A total of 164 clinical isolates of S. maltophilia were collected from hospitals in various regions in Iran between 2016 and 2017. Antibiotic susceptibility testing was performed by disc diffusion method and E-test assay according to the Clinical and Laboratory Standards Institute (CLSI) guideline. The ability of biofilm formation was assessed with crystal violet staining and then, biofilm-associated genes were investigated by PCR-sequencing method. The presence of L1 (a metallo-β-lactamase), L2 (a clavulanic acid-sensitive cephalosporinase), sul1 and sul2 (resistance to Trimethoprim/Sulfamethoxazole), Smqnr (intrinsic resistance to quinolones), and dfrA genes (dihydrofolate reductase enzyme that contributes to trimethoprim resistance) was also examined by PCR-sequencing. Relative gene expression of smeDEF efflux pump was assessed by real-time PCR. Genotyping was performed using the multi-locus sequencing typing (MLST) and repetitive extragenic palindromic-PCR (Rep-PCR). Isolates were resistant to imipenem (100%), meropenem (96%), doripenem (96%), and ceftazidime (36.58%). Notably, 5 (3.04%) isolates showed resistant to trimethoprim-sulfamethoxazole (TMP-SMX), an alarming trend of decreased susceptibility to TMP-SMX in Iran. Minocycline and levofloxacin exhibited the highest susceptibility of 91.46 and 99.39%, respectively. Using the crystal violet staining, 157 (95.73%) isolates had biofilm phenotype: 49 (29.87%), 63 (38.41%), and 45 (27.43%) isolates were categorized as strong-, moderate- and weak-biofilm producer while 7 isolates (4.26%) were identified a non-biofilm producer. Biofilm genes had an overall prevalence of 145 (88.41%), 137 (83.53%), and 164 (100%) of rmlA, rpfF, and spgM, respectively. L1, L2, Smqnr, sul1, and sul2 resistance genes were detected in 145 (88.41%), 156 (96.12%), 103 (62.80%), 89 (54.26%), and 92 (56.09%) isolates, respectively. None of the S. maltophilia isolates were positive for dfrA12, dfrA17, and dfrA27 genes. Gene expression analysis showed that smeD efflux system was overexpressed in two out of the five clinical isolates (40%) that showed resistance to TMP-SMX. Most of the isolates were genetically unrelated. Two new sequence types (ST139 and ST259) were determined. Our results showed that TMP-SMX was still an effective antibiotic against S. maltophilia. The findings of the current study revealed an increasing prevalence of antibiotic resistance and biofilm genes in clinical S. maltophilia isolates in Iran.

Novel trimethoprim resistance gene, dfrA35, in IncC plasmids from Australia.

In Gram-negative bacteria, over 30 different genes are known to encode a trimethoprim-insensitive dihydrofolate reductase that confers resistance to trimethoprim. To determine whether a gene encoding a putative dihydrofolate reductase found in type 2 IncC plasmids isolated between 2002 and 2013 in healthcare facilities in Melbourne, Australia, confers trimethoprim resistance. Conjugation was used to transfer plasmids into a laboratory Escherichia coli. A PCR-amplified fragment was cloned into pUC19 using Gibson Assembly and transformed into E. coli. The level of resistance to trimethoprim was determined using broth microdilution. MEGA (7.0.26) and Geneious Prime (7.0.9) were used to examine the relationship to known Dfr proteins. The conjugative IncC plasmid pEc158 from a 2002 Melbourne clinical E. coli isolate was shown to transfer trimethoprim resistance. The putative DfrA protein encoded by a dfrA gene in pEc158 shares <40% amino acid identity with any previously identified DfrA protein. This gene was cloned and found to confer trimethoprim resistance. The gene and protein were named dfrA35/DfrA35. In pEc158 the dfrA35 gene is located near the ori end of a partial copy of the CR1 element, within a complex resistance island. It is found in the same location in further closely-related type 2 IncC plasmids from Klebsiella pneumoniae (Melbourne, 2013), which were not transfer proficient. Resistance determinants continue to be found and will be missed using website-associated databases to infer phenotypes from genome sequences rather than direct phenotypic testing.

Occurrence of Transferable Integrons and sul and dfr Genes Among Sulfonamide-and/or Trimethoprim-Resistant Bacteria Isolated From Chilean Salmonid Farms.

Salmon farming industry in Chile currently uses a significant quantity of antimicrobials to control bacterial pathologies. The main aims of this study were to investigate the presence of transferable sulfonamide- and trimethoprim-resistance genes, sul and dfr, and their association with integrons among bacteria associated to Chilean salmon farming. For this purpose, 91 Gram-negative strains resistant to sulfisoxazole and/or trimethoprim recovered from various sources of seven Chilean salmonid farms and mainly identified as belonging to the Pseudomonas genus (81.0%) were studied. Patterns of antimicrobial resistance of strains showed a high incidence of resistance to florfenicol (98.9%), erythromycin (95.6%), furazolidone (90.1%) and amoxicillin (98.0%), whereas strains exhibited minimum inhibitory concentrations (MIC90) values of sulfisoxazole and trimethoprim of >4,096 and >2,048 μg mL−1, respectively. Strains were studied for their carriage of these genes by polymerase chain reaction, using specific primers, and 28 strains (30.8%) were found to carry at least one type of sul gene, mainly associated to a class 1 integron (17 strains), and identified by 16S rRNA gene sequencing as mainly belonging to the Pseudomonas genus (21 strains). Of these, 22 strains carried the sul1 gene, 3 strains carried the sul2 gene, and 3 strains carried both the sul1 and sul2 genes. Among these, 19 strains also carried the class 1 integron-integrase gene intI1, whereas the dfrA1, dfrA12 and dfrA14 genes were detected, mostly not inserted in the class 1 integron. Otherwise, the sul3 and intI2 genes were not found. In addition, the capability to transfer by conjugation these resistance determinants was evaluated in 22 selected strains, and sul and dfr genes were successfully transferred by 10 assayed strains, mainly mediated by a 10 kb plasmid, with a frequency of transfer of 1.4 × 10−5 to 8.4 × 10−3 transconjugant per recipient cell, and exhibiting a co-transference of resistance to florfenicol and oxytetracycline, currently the most used in Chilean salmon industry, suggesting an antibacterial co-selection phenomenon. This is the first report of the characterization and transferability of integrons as well as sul and dfr genes among bacteria associated to Chilean salmon farms, evidencing a relevant role of this environment as a reservoir of these genes.

Distribution and characteristics of SGI1/PGI2 genomic island from Proteus strains in China

The emergence of multidrug-resistant Salmonella genomic island 1 (SGI1) and Proteus genomic island (PGI) bearing P. mirabilis present a serious threat to public health. In this study, we screened 288 Proteus isolates recovered from seven provinces in China. Fourteen strains (4.9%) all belonged to P. mirabilis were positive for SGI1/PGI2, including twelve from clinical samples (5.3%) and two from food (3.3%). A Blastn search against GenBank and phylogenetic analyses identified eight different SGI1 variants and one PGI2 variant from the fourteen SGI1/PGI2 variants. All SGI1 variants shared a common backbone and harbored different resistance gene(s), except the sul1 gene at its multidrug-resistant (MDR) region. Among the variants, three novel SGI1 variants, designated as SGI1-PmCA11, SGI1-PmCA14 and SGI1-PmCA46, contained different gene cassettes, which were similar to sequences in plasmids or class 1 integrons of Klebsiella pneumoniae, P. mirabilis, Escherichia coli and Salmonella. Moreover, one novel PGI2, designated as PGI2-PmCA72, had an identical gene cassette to the first class 1 integron from PGI2 (GenBank accession no. MG201402.1) in P. mirabilis, but varied due to missing, replaced, inserted and inverted gene clusters. The four novel SGI1/PGI2 variants contained the cmlA5, dfrA14, blaOXA-10, aadA15, blaOXA-1, catB3 and dfrA16 resistance genes, which have never been reported in SGI1/PGI2 variants. Phenotypically, all fourteen SGI1/PGI2-containing strains showed multidrug resistance. All except four strains were resistant to the first, or the second and/or-third generation cephalosporins. Considering the increasing number and the emergence of new SGI1/PGI2 variants, further surveillance is needed to prevent the spreading of the MDR genomic islands among Proteus isolates from human and food.

Proteae: a reservoir of class 2 integrons?

Our aim was to confirm with a large panel of clinical isolates that class 2 integrons are highly prevalent in Proteae and to analyse their genetic characteristics. Proteae (Proteus spp., Morganella spp. and Providencia spp.) isolates were collected from clinical samples during 2013 at Limoges University Hospital, France. The presence of class 1, 2 and 3 integrons was investigated by quantitative PCR. The presence of a stop codon in the intI2 gene was determined by Sanger sequencing. The gene cassette arrays of class 2 integrons were determined by PCR-RFLP and Sanger sequencing or next-generation sequencing when needed. Of the 327 Proteae collected, 103 (31.5%) harboured a class 2 integron and 45 (13.8%) a class 1 integron. No class 3 integrons were detected. One functional IntI2 integrase was detected in a Morganella morganii isolate. Six different gene cassette arrays were detected. Four had already been described in the literature: dfrA1-sat2-aadA1 (72 isolates), dfrA1-catB2-sat2-aadA1 (17), sat2-aadA1 (6) and lnu(F), dfrA1, aadA1 (1). We identified two new gene cassette arrays: (i) a new variant of the dfrA1 gene cassette (one isolate; the one with the functional IntI2); and (ii) the array dfrA1-gcu115-sat2 harbouring the new gcu115 gene cassette with two ORFs encoding proteins of unknown functions (five isolates). We showed a high frequency of class 2 integrons, as well as a diversity of gene cassette arrays, among Proteae. This work highlights that the Proteae tribe plays an important role as a reservoir of class 2 integrons.

Plasmid-located dfrA14 gene in Pasteurella multocida isolates from three different pig-producing farms in Germany

Pasteurella multocida is an important respiratory tract pathogen in intensive livestock farming, especially in pigs. Antimicrobial agents are frequently used to combat infections caused by this pathogen. In a study on antimicrobial resistance among respiratory tract pathogens of pigs from 30 German pig-producing farms, P. multocida isolates (n = 9) with high minimal inhibitory concentration (MIC) values of 16/304 mg/L (n = 2), 32/608 mg/L (n = 3) or ≥64/1216 mg/L (n = 4) for trimethoprim/sulfamethoxazole (1:19) and of ≥512 mg/L (n = 9) for trimethoprim (TMP) were detected in three of these farms. The genetic relatedness of the isolates was investigated via capsule-specific PCR and macrorestriction analyses with ApaI and SmaI. Pulsed-field gel electrophoresis revealed indistinguishable restriction patterns per farm, with slight differences between the three farms. All isolates represented capsular type A. Four representative isolates, that were subjected to whole genome sequencing, shared the multi-locus sequence type (ST) 3. Their plasmids were transformed into E. coli TOP10 with subsequent selection on TMP-containing agar plates. Antimicrobial susceptibility testing and plasmid analysis of the transformants confirmed that they were resistant to sulfonamides and trimethoprim and carried only a single small plasmid. This plasmid was completely sequenced and revealed a size of 6050 bp. Sequence analyses identified the presence of a resistance gene cluster comprising the genes sul2-ΔstrA-dfrA14-ΔstrA-ΔstrB. Further analysis identified a dfrA14 gene cassette being integrated into the strA reading frame. Neither the gene dfrA14 nor this gene cluster have been detected before in P. multocida.

Detection Some Pathogenic Bacteria Causing UTI in Type 2 Diabetic Patients and Determine Some Resistance Genes in Escherichia coli by PCR in Kirkuk City

Determine some types of bacteria that cause urinary tract infection among type 2 diabetes mellitus patients. A cross-sectional study was carried out among 210 patients selected by using non probability sampling (purposive sampling). According to study findings females were 64.3% of the study sample, most of them were an elderly age, 26.2% of them had positive urine culture and Escherichia coli was the most common cause of UTI and then Klebsiella pneumoniae and Staphylococcus aureus. Sensitivity tests were done to determine resistance of bacteria to antibiotic that used in this study and determine some of the resistance genes in E. coli. The gyrA gene and dfrA1 gene are found in resistance isolates of E. coli to Nalidixic acid and Trimethoprim respectively.

Detection of some resistance genes in &lt;i&gt;Salmonella&lt;/i&gt; isolated from Poultry farms in Abia and Imo States, Southeastern Nigeria

Sixteen Salmonella Gallinarum and 24 Salmonella Pullorum strains isolated from chickens were screened for resistance to 11 antibacterial agents using the disc diffusion method. Five of the Salmonella Gallinarum and five of S. Pullorum strains resistant to streptomycin, gentamicin, tetracycline and sulfamethoxazole /trimethoprim were screened for presence of strA/strB, aac (3)-II, aac (3)-1V, tetA and tetB and sul 1 (dfr/A) and sul 3 (dfr/G) resistance genes. A singleplex PCR with resistance gene specific primers was used to ascertain the presence of the target resistance gene. All the Salmonella isolates studied were resistant to ampicillin while 95% were resistant to tetracycline and streptomycin. None of the isolates were resistant to ofloxacin and ciprofloxacin. Three of the sulphamethaxazole/trimethoprim-resistant isolates haboured dfrA and dfrG genes while one of the gentamicin-resistant isolates was positive for aac (3)-II genes. None out of the 10 streptomycin and tetracycline resistant isolates harbored any strA/strB, tetA and tetB genes. In addition, none of the 10 gentamicin resistant isolates harbored aac (3)-IV genes. The high resistance rates recorded in this study may be attributed to indiscriminate use of antibacterial agents.Keywords: Salmonella, antimicrobials, resistance genes, Polymerase chain reaction, Southeastern Nigeria

Novel trimethoprim resistance gene dfrA34 identified in Salmonella Heidelberg in the USA.

Trimethoprim/sulfamethoxazole is a synthetic antibiotic combination recommended for the treatment of complicated non-typhoidal Salmonella infections in humans. Resistance to trimethoprim/sulfamethoxazole is mediated by the acquisition of mobile genes, requiring both a dfr gene (trimethoprim resistance) and a sul gene (sulfamethoxazole resistance) for a clinical resistance phenotype (MIC ≥4/76 mg/L). In 2017, the CDC investigated a multistate outbreak caused by a Salmonella enterica serotype Heidelberg strain with trimethoprim/sulfamethoxazole resistance, in which sul genes but no known dfr genes were detected. To characterize and describe the molecular mechanism of trimethoprim resistance in a Salmonella Heidelberg outbreak isolate. Illumina sequencing data for one outbreak isolate revealed a 588 bp ORF encoding a putative dfr gene. This gene was cloned into Escherichia coli and resistance to trimethoprim was measured by broth dilution and Etest. Phylogenetic analysis of previously reported dfrA genes was performed using MEGA. Long-read sequencing was conducted to determine the context of the novel dfr gene. The novel dfr gene, named dfrA34, conferred trimethoprim resistance (MIC ≥32 mg/L) when cloned into E. coli. Based on predicted amino acid sequences, dfrA34 shares less than 50% identity with other known dfrA genes. The dfrA34 gene is located in a class 1 integron in a multiresistance region of an IncC plasmid, adjacent to a sul gene, thus conferring clinical trimethoprim/sulfamethoxazole resistance. Additionally, dfrA34 is associated with ISCR1, enabling easy transmission between other plasmids and bacterial strains.

Frozen White-Leg Shrimp (Litopenaeus vannamei) in Korean Markets as a Source of Aeromonas spp. Harboring Antibiotic and Heavy Metal Resistance Genes.

As the most consumed shrimp variety, white-leg shrimp (Litopenaeus vannamei) owns a high market demand in Korea. This study sought to screen the frozen white-leg shrimp for Aeromonas spp. harboring antimicrobial and heavy metal resistance characteristics. A total of 44 Aeromonas spp. strains were isolated and tested for antibiotic susceptibility and heavy metal tolerance followed by PCR-based detection of resistance genes and integrons. It was observed that resistance to ampicillin and oxacillin was 100% among isolates. Besides, 95%, 89%, 86%, 80%, 66%, and 43% of the isolates were resistant to nalidixic acid, tetracycline, cephalothin, streptomycin, trimethoprim-sulfamethoxazole, and imipenem, respectively, and less resistance to other antibiotics was also observed. Cr resistance was the highest (91%) among five heavy metals tested, whereas 57%, 32%, 20%, and 9% of the isolates were tolerant to Cu, Pb, Cd, and Hg, respectively. The PCR assays implied the presence of qnrB, qnrS, tetA, tetE, aac(6')-Ib, and aphAI-IAB, and intI1 genes among 80%, 77%, 18%, 30%, 9%, 0.25%, and 82% of the isolates, respectively. There were 35 (80%) integron 1-positive isolates harboring qacE2, dfrA1, orfC, orfD, aadB, catB3, oxa-10, and aadA1 genes in varying combinations. In addition, heavy metal resistance genes, CopA, merA, and CzcA were positive in 9%, 7%, and 27% of the isolates, respectively. According to these outcomes, the frozen white-leg shrimp in Korean markets can be suggested as a source of multidrug and heavy metal-resistant Aeromonas spp. that carries genetic determinants.

Whole genome sequencing of multidrug-resistant Salmonella enterica serovar Typhimurium isolated from humans and poultry in Burkina Faso

BackgroundMultidrug-resistant Salmonella is an important cause of morbidity and mortality in developing countries. The aim of this study was to characterize and compare multidrug-resistant Salmonella enterica serovar Typhimurium isolates from patients and poultry feces.MethodsSalmonella strains were isolated from poultry and patients using standard bacteriological methods described in previous studies. The strains were serotype according to Kaufmann-White scheme and tested for antibiotic susceptibility to 12 different antimicrobial agents using the disk diffusion method. The whole genome of the S. Typhimurium isolates was analyzed using Illumina technology and compared with 20 isolates of S. Typhimurium for which the ST has been deposited in a global MLST database.The ResFinder Web server was used to find the antibiotic resistance genes from whole genome sequencing (WGS) data. For comparative genomics, publicly available complete and draft genomes of different S. Typhimurium laboratory-adapted strains were downloaded from GenBank.ResultsAll the tested Salmonella serotype Typhimurium were multiresistant to five commonly used antibiotics (ampicillin, chloramphenicol, streptomycin, sulfonamide, and trimethoprim). The multilocus sequence type ST313 was detected from all the strains. Our sequences were very similar to S. Typhimurium ST313 strain D23580 isolated from a patient with invasive non-typhoid Salmonella (NTS) infection in Malawi, also located in sub-Saharan Africa. The use of ResFinder web server on the whole genome of the strains showed a resistance to aminoglycoside associated with carriage of the following resistances genes: strA, strB, and aadA1; resistance to β-lactams associated with carriage of a blaTEM-1B genes; resistance to phenicol associated with carriage of catA1 gene; resistance to sulfonamide associated with carriage of sul1 and sul2 genes; resistance to tetracycline associated with carriage of tet B gene; and resistance to trimethoprim associated to dfrA1 gene for all the isolates.ConclusionThe poultry and human isolates were genetically similar showing a potential food safety risk for consumers. Our finding of multidrug-resistant S. Typhimurium ST313 in poultry feces calls for further studies to clarify the potential reservoirs of this emerging pathogen.

Complexity of Antibiotic Resistance in Commensal Escherichia coli Derived from Pigs from an Intensive-Production Farm.

Antibiotics in animal husbandry are used to maintain welfare, but lead to the generation of resistant strains. We analyzed commensal multidrug-resistant Escherichia coli from pigs at the beginning and end of the production cycle in a farm with a farrow-to-finish system in order to investigate whether clonal spread or horizontal gene transfer constitutes the main factor responsible for the prevalence of resistance in this environment. Among 380 isolates, 56 multidrug-resistant E. coli with a similar resistant phenotype were selected for more detailed investigations including a genomic similarity analysis and the detection of mobile elements. Isolates carried blaTEM-1, aadA1, strA/B, tetA, tetB, tetC, dfrA1, dfrA5, dfrA7, dfrA12, sul1, sul2, sul3, and qnrS resistance genes, with the common co-occurrence of genes encoding the same resistance phenotype. A pulse-field gel electrophoresis analysis of the genomic similarity of multidrug-resistant E. coli showed ≤65% similarity of most of the tested strains and did not reveal a dominant clone responsible for the prevalence of resistance. Class 1 and 2 integrons and transposons 7 and 21 were detected among mobile elements; however, some were truncated. Plasmids were represented by 11 different incompatibility groups (K, FIB, I1, FIIA, FIC, FIA, Y, P, HI1, B/O, and T). Genetic resistance traits were unevenly spread in the clonal groups and suggested the major rearrangement of genetic material by horizontal gene transfer. The present results revealed that in commensal E. coli from pigs in a homogeneous farm environment, there was no dominant clone responsible for the spread of resistance and persistence in the population.

Class 1 integrons and plasmid-mediated multiple resistance genes of the Campylobacter species from pediatric patient of a university hospital in Taiwan

BackgroundThe Campylobacter species usually causes infection between humans and livestock interaction via livestock breeding. The studies of the Campylobacter species thus far in all clinical isolates were to show the many kinds of antibiotic phenomenon that were produced. Their integrons cause the induction of antibiotic resistance between bacterial species in the Campylobacter species.ResultsThe bacterial strains from the diarrhea of pediatric patient which isolated by China Medical University Hospital storage bank. These isolates were identified by MALDI-TOF mass spectrometry. The anti-microbial susceptibility test showed that Campylobacter species resistant to cefepime, streptomycin, tobramycin and trimethoprim/sulfamethoxazole (all C. jejuni and C. coli isolates), ampicillin (89% of C. jejuni; 75% of C. coli), cefotaxime (78% of C. jejuni; 100% of C. coli), nalidixic acid (78% of C. jejuni; 100% of C. coli), tetracycline (89% of C. jejuni; 25% C. coli), ciprofloxacin (67% of C. jejuni; 50% C. coli), kanamycin (33% of C. jejuni; 75% C. coli) and the C. fetus isolate resisted to ampicillin, cefotaxime, nalidixic acid, tetracycline, ciprofloxacin, kanamycin by disc-diffusion method. The effect for ciprofloxacin and tetracycline of the Campylobacter species was tested using an E-test. The tet, erm, and integron genes were detected by PCR assay. According to the sequencing analysis (type I: dfr12-gcuF-aadA2 genes and type II: dfrA7 gene), the cassette type was identified. The most common gene cassette type (type I: 9 C. jejuni and 2 C. coli isolates; type II: 1 C. coli isolates) was found in 12 class I integrase-positive isolates.ConclusionsOur results suggested an important information in the latency of Campylobacter species with resistance genes, and irrational antimicrobial use should be concerned.

Integron types, gene cassettes and antimicrobial resistance profile of Acinetobacter baumannii isolated from BAL samples in Babol, north of Iran

Multi-drug resistant isolates of Acinetobacter baumannii have created therapeutic problems worldwide. This current study was intended to determine the Integron types, gene cassettes and antimicrobial resistance profile of A.baumannii isolated from BAL samples in Babol, north of Iran. During a 15-month period, 35 A.baumannii isolates were studied. Different classes of antimicrobial agents were used to determine the resistance ratios. Multiplex-PCR was used to detect different types of integrons and associated gene cassettes. The resistance rates to GM, FEP, AK, TOB, CP, PIP, SAM, IPM, SXT, CTX, CAZ, CL, TIM, MEM, and TZP were 85.7%, 100%, 91.4%, 68.5%, 94.3%, 88.5%, 97.1%, 94.3%, 100%, 100%, 100%, 0.0%, 91.4%, 94.3% and 91.4%, respectively. The distribution analysis of int genes showed that 25.7%, 88.6% and 28.6% of isolates carried the intI, intII and intIII genes, respectively. The prevalence of aadB, dfrA1, bla-OXA30 and aadA1 genes were 94.3%, 77.1%, 40% and 5.7%, respectively. The current study showed that a high level of A.baumannii isolates harbor integrons in our therapeutic center, which may lead to distribution of multiple antimicrobial resistance. The different types of gene cassette arrays in the present study highlight the important role of geographical features in MDR isolates dissemination which could be credited to different profiles of drug consumption in different areas. The findings emphasized that the need for continuous surveillance to prevent distribution of multidrug resistance among A.baumannii strains in Iran.

Stenotrophomonas maltophilia in a university hospital of traditional Chinese medicine: molecular epidemiology and antimicrobial resistance

Stenotrophomona maltophilia has emerged as an important opportunistic pathogen that is highly antibiotic resistant. Analysis of antibiotic susceptibilities, drug-resistant gene profiles and molecular typing of S. maltophilia was undertaken in a university hospital of traditional Chinese medicine in East China. Resistance to sulphamethoxazole (SXT) was found to be an indicator of multi-drug resistance. SXT resistance was mediated by sul and dfrA genes in integrons, especially class 1. Some evidence of clonal dissemination was found, indicating the occurrence of cross-transmission of antibiotic-resistant strains within the hospital. This underscores the need for effective control and prevention measures in hospitals.

English

Food-borne diseases represent a public major health problem, and drink-water, juice, meat, and milk products are usually involved. This study aimed to evaluate the antibiotic resistance of diarrheagenic E. coli isolated from dairy products consumed in Burkina Faso. Five hundred and twenty-two samples were gathered. Escherichia coli were isolated using Standard Microbiological Methods. A 16-plex polymerase chain reaction for virulence associated genes was applied. The standard disc diffusion methods were used to assess the susceptibility to 31 antibiotics. Classes 1, 2, 3 integrons were categorized using PCR. Results showed 1.92% (10/522) of milk products was contaminated by diarrheagenic E. coli. Enterotoxinogenic E. coli was found in 4.45% (4/89) of curds, 3.4% (3/88) of pasteurized milk, and 1.15% (1/87) of &ldquo;d&eacute;gu&egrave;&rdquo;. Also, &ldquo;d&eacute;gu&egrave;&rdquo; was contaminated at 2.3% (2/87) by atypical enteropathogenic E. coli. Antibiogram susceptibility showed that pathogenic isolated resists mainly to tetracycline, amoxicillin, ticarcillin, nalidixic acid, sulfonamide, and trimethoprim-sulfamethoxazole. Only the class 1 integrons was detected in 80% of diarrheagenic E. coli. Among this class 1 integrons, 4 strains contains a variable region, and the subsequent result showed a presence of dfrA7 gene coding for trimethoprim resistance. It appears in this study that dairy products are contaminated by enteropathogenic and enterotoxinogenic E. coli, which are resistant to antibiotics frequently used. This study therefore recommends the training of milk products transformers. &nbsp; Key words: Dairy products, diarrheagenic Escherichia coli, antibiotics resistance, integrons, Burkina Faso.