Strains Of Serotype Research Articles

Conventional and molecular detection of vibrio cholerae isolated from environmental water with the prevalence of antibiotic resistance mechanisms.

Environmental water is an important source for Vibrio cholerae, which is autochthonous to the aquatic environment, monitoring this bacterium in water is important for control of cholera. Vibrio cholerae represents an enormous public health problem around the world, especially in developing countries. One hundred samples were collected and selected. The samples were filtered and transferred to slants containing 2ml of alkaline peptone water, then subcultured on selective medium Thiosulphate Citrate Bile Salt Sucrose agar. All presumptive isolates were confirmed by using a series of biochemical tests including Oxidase test, Simmon Citrate test, DNase test, Indole test, Klingler Iron Agar (KIA) test, MacConkey agar test and motility. Confirmed Vibrio cholera strains were then screening for slide agglutination test by using commercially antisera polyvalent and monovalent O1 and O139 for determining strain serotype. The DNA extracted from pure culture and Polymerase Chain Reaction assay was used for molecular detection of Vibrio cholerae, a specific primer which designed according to ctxA gene sequences. This primer was detection and amplifying 241 base pairs of the ctxA gene. The resistance to antibiotics by Vibrio cholerae was determining by using thirteen standardized disc diffusion including Amikacin, Ceftriaxone, Ceftazidime, Gentamycin, Tetracycline, Streptomycin, Tobramycin, Cephotaxime, Nalidixic Acid, Norfloxacin, Cephalothin, Rifampicin, Cefixime. From one hundred water samples were detected, fifty-six samples were motile and positive for biochemical tests. Fifteen isolates confirmed as Vibrio cholera by Polymerase Chain Reaction (PCR) assay with primers de­signed for ctxA and 241bp band was observed. These fifteen isolates showed agglutination with polyvalent and monovalent O1 antisera, and two strains represented Ogawa from other strains that showed Inaba. The fifteen isolates exhibited an identical response to each antibiotic examined. They showed sensitive to all antibiotics except Amikacin, Streptomycin, Cefixime, Norfloxacin, Cephalothin. the aim of this study was determined the accurate method for detection of Vibrio cholerae in environmental water. In the current study, we found that the molecular method using Polymerase Chain Reaction performance using the ctxA gene-specific primers for detection of Vibrio cholerae was faster and accurate and specific.

Redefining the Small Regulatory RNA Transcriptome in Streptococcus pneumoniae Serotype 2 Strain D39.

Streptococcus pneumoniae (pneumococcus) is a major human respiratory pathogen and a leading cause of bacterial pneumonia worldwide. Small regulatory RNAs (sRNAs), which often act by posttranscriptionally regulating gene expression, have been shown to be crucial for the virulence of S. pneumoniae and other bacterial pathogens. Over 170 putative sRNAs have been identified in the S. pneumoniae TIGR4 strain (serotype 4) through transcriptomic studies, and a subset of these sRNAs has been further implicated in regulating pneumococcal pathogenesis. However, there is little overlap in the sRNAs identified among these studies, which indicates that the approaches used for sRNA identification were not sufficiently sensitive and robust and that there are likely many more undiscovered sRNAs encoded in the S. pneumoniae genome. Here, we sought to comprehensively identify sRNAs in Avery's virulent S. pneumoniae strain D39 using two independent RNA sequencing (RNA-seq)-based approaches. We developed an unbiased method for identifying novel sRNAs from bacterial RNA-seq data and have further tested the specificity of our analysis program toward identifying sRNAs encoded by both strains D39 and TIGR4. Interestingly, the genes for 15% of the putative sRNAs identified in strain TIGR4, including ones previously implicated in virulence, are not present in the strain D39 genome, suggesting that the differences in sRNA repertoires between these two serotypes may contribute to their strain-specific virulence properties. Finally, this study has identified 66 new sRNA candidates in strain D39, 30 of which have been further validated, raising the total number of sRNAs that have been identified in strain D39 to 112.IMPORTANCE Recent work has shown that sRNAs play crucial roles in S. pneumoniae pathogenesis, as inactivation of nearly one-third of the putative sRNA genes identified in one study led to reduced fitness or virulence in a murine model. Yet our understanding of sRNA-mediated gene regulation in S. pneumoniae has been hindered by limited knowledge about these regulatory RNAs, including which sRNAs are synthesized by different S. pneumoniae strains. We sought to address this problem by developing a sensitive sRNA detection technique to identify sRNAs in S. pneumoniae D39. A comparison of our data set reported here to those of other RNA-seq studies for S. pneumoniae strain D39 and TIGR4 has provided new insights into the S. pneumoniae sRNA transcriptome.

Diversity patterns of bacteriophages infecting Aggregatibacter and Haemophilus species across clades and niches

Aggregatibacter and Haemophilus species are relevant human commensals and opportunistic pathogens. Consequently, their bacteriophages may have significant impact on human microbial ecology and pathologies. Our aim was to reveal the prevalence and diversity of bacteriophages infecting Aggregatibacter and Haemophilus species that colonize the human body. Genome mining with comparative genomics, screening of clinical isolates, and profiling of metagenomes allowed characterization of 346 phages grouped in 52 clusters and 18 superclusters. Less than 10% of the identified phage clusters were represented by previously characterized phages. Prophage diversity patterns varied significantly for different phage types, host clades, and environmental niches. A more diverse phage community lysogenizes Haemophilus influenzae and Haemophilus parainfluenzae strains than Aggregatibacter actinomycetemcomitans and “Haemophilus ducreyi”. Co-infections occurred more often in “H. ducreyi”. Phages from Aggregatibacter actinomycetemcomitans preferably lysogenized strains of specific serotype. Prophage patterns shared by subspecies clades of different bacterial species suggest similar ecoevolutionary drivers. Changes in frequencies of DNA uptake signal sequences and guanine–cytosine content reflect phage-host long-term coevolution. Aggregatibacter and Haemophilus phages were prevalent at multiple oral sites. Together, these findings should help exploring the ecoevolutionary forces shaping virus-host interactions in the human microbiome. Putative lytic phages, especially phiKZ-like, may provide new therapeutic options.

Novel Yersinia enterocolitica Prophages and a Comparative Analysis of Genomic Diversity.

Yersinia enterocolitica is a major agent of foodborne diseases worldwide. Prophage plays an important role in the genetic evolution of the bacterial genome. Little is known about the genetic information about prophages in the genome of Y. enterocolitica, and no pathogenic Y. enterocolitica prophages have been described. In this study, we induced and described the genomes of six prophages from pathogenic Y. enterocolitica for the first time. Phylogenetic analysis based on whole genome sequencing revealed that these novel Yersinia phages are genetically distinct from the previously reported phages, showing considerable genetic diversity. Interestingly, the prophages induced from O:3 and O:9 Y. enterocolitica showed different genomic sequences and morphology but highly conserved among the same serotype strains, which classified into two diverse clusters. The three long-tailed Myoviridae prophages induced from serotype O:3 Y. enterocolitica were highly conserved, shared ≥99.99% identity and forming genotypic cluster A; the three Podoviridae prophages induced from the serotype O:9 strains formed cluster B, also shared more than 99.90% identity with one another. Cluster A was most closely related to O:5 non-pathogenic Y. enterocolitica prophage PY54 (61.72% identity). The genetic polymorphism of these two kinds of prophages and highly conserved among the same serotype strains, suggested a possible shared evolutionary past for these phages: originated from distinct ancestors, and entered pathogenic Y. enterocolitica as extrachromosomal genetic components during evolution when facing selective pressure. These results are critically important for further understanding of phage roles in host physiology and the pathology of disease.

Presence of bluetongue and epizootic hemorrhagic disease viruses in Egypt in 2016 and 2017

BTV and EHDV are closely-related orbiviruses that are transmitted between domestic and wild ruminants via the bites of hematophagous midges. Previous studies have reported seropositivity against BTV antibodies in sheep and goats in two Egyptian governorates (Beni Suef and Menoufia). However, no recent data are available on the BTV serotype(s) circulating in Egypt and the likely presence of EHDV has never been explored. This study investigated the presence of BTV and EHDV among cattle which had been found BTV-seropositive by ELISA method. These cattle living in proximity to sheep and goats previously found BTV-seropositive. These cattle displayed no clinical signs of BT but reproductive problems had been reported in herds. A total of 227 cattle blood samples were therefore collected in 2016 and 2017. Ninety-four of the 227 animals tested by a BTV ELISA were positive for BTV antibodies (41.4%). Of these 94 ELISA-positive cattle, only 83 EDTA-blood samples were available and therefore tested for BTV and EHDV genome detection by RT-PCR and sequencing.Of the cattle sampled in 2016, results revealed that two were RT-PCR-positive for BTV and seven for EHDV. Sequencing showed the presence of EHDV-1 and BTV-3 genome sequences. EHDV-1 S2 shared 99.5% homology with an EHDV-1 S2 from a strain isolated in 2016 in Israel. BTV-3 S2 and S8 sequences shared >99.8% nucleotide similarity with the BTV-3 Zarzis S2 and S8 sequences (Tunisian BTV, also detected in 2016). Of the 66 blood samples tested following their collection in 2017, they were all EHDV-negative by RT-qPCR while five were BTV- positive by RT-qPCR. However, attempts to identify the BTV serotype of these five samples were unsuccessful. Only part of BTV S8 was sequenced and it showed 79% nucleotide similarity with S8 of atypical BTV serotypes (particularly with BTV-26 and another BTV serotype strain isolated from a sheep pox vaccine). Overall, these findings demonstrate that both BTV and EHDV were circulating in Egypt in 2016 and 2017.

Serotyping Isolated Strains of Salmonella for Consomption in the Eastern Logone Province in Chad

The present work was carried out in the Doba petroleum basin, Eastern Logone Province, and focused on the serotyping of strains of salmonella isolated in well water, boreholes and rivers for the consumption of the population. The sampling was carried out according to a complete randomized device with 10 samples per source of water, making a total of 30 samples. Salmonellae were detected according to the French standard ISO 6579: 2002, followed by serotyping. The results of the biochemical identification test of the API 20 E gallery led, thanks to the Apiweb Tm-API 20E V4.1 site to Salmonella spp. The serotyping results revealed, according to the White-Kauffmann-Le Minor table, serovars Anatum, Mbandaka and Idikan. S. Anatum was detected in P4 well waters and F6 wells; S. Mbandaka, in F9 and R8 river water; and finally, S. Idikan, in F5 and R4 river water. These results show a homogeneous distribution of these serotypes in the different water sources of the study area. The presence of these pathogenic serotypes in drinking water sources attests that these waters are unhealthy in accordance with WHO's guidelines for drinking quality. Corrective measures are needed to improve the quality of these water rich in germs that may cause food poisoning.

Identification of a conserved linear epitope using monoclonal antibody against non-structural protein 3A of foot-and-mouth disease virus with potential for differentiation between infected and vaccinated animals

Foot-and-mouth disease (FMD) is a highly contagious and economically devastating viral disease of cloven-hoofed animals. Vaccination is a key element in the control of FMD among countries where the disease is enzootic. Differentiating infected from vaccinated animals in herds after immunization is an important component of effective eradication strategies. Non-structural protein (NSP) 3A of FMDV is as part of a larger detected antigen that is used for this differential diagnosis. Here, we generated a specific monoclonal antibody (MAb) against FMDV non-structural protein called 3A10, and further defined the linear epitopes recognized by the MAb 3A10 using a series of peptides that expressed GST-fused protein. Using Western blot, it was showed that the 5-aa peptide 126ERTLP130 of 3A was the minimal epitope reactive to MAb 3A10. Alanine-scanning mutagenesis analysis revealed that Arg127 and Leu129 were crucial for MAb 3A10 binding to 126ERTLP130. Furthermore, sequence alignment analysis, indicated that the epitope 126ERTLP130 recognized by 3A10 was shown to be conserved among seven serotypes of FMDV strains. The synthetic peptide Elisa demonstrated that this epitope peptide could be recognized by sera from FMDV-infected pigs and cattle, but negative reactivity to unvaccinated and vaccinated healthy animal sera. Thus, the MAb reagents and the linear epitopes defined herein provide theoretical and technical support for the development of diagnostic tools for infection differentiating FMDV infected from vaccinated animals.

Whole genome sequencing used in an industrial context reveals a Salmonella laboratory cross-contamination

In 2013, during a routine laboratory analysis performed on food samples, one finished product from a European factory was tested positive for Salmonella Hadar. At the same period, one environmental isolate in the same laboratory was serotyped Salmonella Hadar. Prior to this event, the laboratory performed a proficiency testing involving a sample spiked with NCTC 9877 Salmonella Hadar. The concomitance of Salmonella Hadar detection led to the suspicion of a laboratory cross-contamination between the Salmonella Hadar isolate used in the laboratory proficiency testing and the Salmonella Hadar isolate found on the finished product by the same laboratory. Since the classical phenotypic serotyping method is able to attribute a serotype to Salmonella isolates with a common antigenic formula, but cannot differentiate strains of the same serotype within the subspecies, whole genome sequencing was used to test the laboratory cross-contamination hypothesis. Additionally, 12 Salmonella Hadar from public databases, available until the time of the event, were included in the whole genome sequencing analysis to better understand the genomic diversity of this serotype in Europe. The outcome of the analysis showed a maximum of ten single nucleotide polymorphisms (SNPs) between the isolates coming from the laboratory and the finished product, and thus confirmed the laboratory cross-contamination. These results combined with all additional investigations done at the factory, allowed to release finished product batches produced and thus circumvented unnecessary food waste and economic losses for the factory.

African Horse Sickness virus: pathogenicity in an IFNAR(-/-) mouse model of infection

African Horse Sickness (AHS) is a highly lethal, vector-borne viral disease of equids, endemic to sub-Saharan Africa but with a history of outbreaks into Europe. The pathogenesis of the virus is not fully understood; some studies have shown that certain proteins are linked to virulence, and that the outcome of infection is highly dependent on viral factors. Disease can also manifest with several different presentations in the equine host (fever form, cardiac form, pulmonary form and mixed form) but the mechanism underlying this variation is not fully understood. Pathogenicity and virulence studies of AHSV are difficult to perform in horses for logistical, ethical and financial reasons. As an alternative, Interferon-alpha receptor knockout (IFNAR-/-) mice have previously been used in AHSV vaccinology studies. Full pathology characterization of the AHSV infection in this model is the primary objective of our work, which will address questions regarding pathogenesis of AHSV. Here we present data collected from experimental infection of IFNAR (-/-) mice with a strain of AHSV serotype 4, including: clinical signs; histopathology; immuno-histochemical analysis of immune response to infection; antigen detection in tissues; and transmission electron microscopy of AHSV infected tissues. In addition, we will show data from experimental infection in this animal model comparing the pathogenicity of different AHSV strains. Results obtained indicate AHSV-4 infection is correlated with oedema and pneumonia in the lungs, inflammation in the liver and meningitis plus perivascular cuffing in the cerebrum. Other data shows that different strains of AHSV differ in terms of their pathogenicity and tropism.

Evidence of reduced viremia, pathogenicity and vector competence in a re-emerging European strain of bluetongue virus serotype 8 in sheep.

SummaryThe outbreak of bluetongue virus (BTV) serotype 8 (BTV‐8) during 2006–2009 in Europe was the most costly epidemic of the virus in recorded history. In 2015, a BTV‐8 strain re‐emerged in France which has continued to circulate since then. To examine anecdotal reports of reduced pathogenicity and transmission efficiency, we investigated the infection kinetics of a 2007 UK BTV‐8 strain alongside the re‐emerging BTV‐8 strain isolated from France in 2017. Two groups of eight BTV‐naïve British mule sheep were inoculated with 5.75 log10TCID50/ml of either BTV‐8 strain. BTV RNA was detected by 2 dpi in both groups with peak viraemia occurring between 5–9 dpi. A significantly greater amount of BTV RNA was detected in sheep infected with the 2007 strain (6.0–8.8 log10 genome copies/ml) than the re‐emerging BTV‐8 strain (2.9–7.9 log10 genome copies/ml). All infected sheep developed BTV‐specific antibodies by 9 dpi. BTV was isolated from 2 dpi to 12 dpi for 2007 BTV‐8‐inoculated sheep and from 5 to 10 dpi for sheep inoculated with the remerging BTV‐8. In Culicoides sonorensis feeding on the sheep over the period 7–12 dpi, vector competence was significantly higher for the 2007 strain than the re‐emerging strain. Both the proportion of animals showing moderate (as opposed to mild or no) clinical disease (6/8 vs. 1/8) and the overall clinical scores (median 5.25 vs. 3) were significantly higher in sheep infected with the 2007 strain, compared to those infected with the re‐emerging strain. However, one sheep infected with the re‐emerging strain was euthanized at 16 dpi having developed severe lameness. This highlights the potential of the re‐emerging BTV‐8 to still cause illness in naïve ruminants with concurrent costs to the livestock industry.

Identification of six novel capsular polysaccharide loci (NCL) from Streptococcussuis multidrug resistant non-typeable strains and the pathogenic characteristic of strains carrying new NCLs.

Streptococcussuis is a major swine pathogen and an important zoonotic agent worldwide. At least nine serotypes can infect human so far. Although 29 serotypes (1-19, 21, 23-25, 27-31 and 1/2) strains are considered as authentic S.suis, a novel variant serotype Chz and strains carrying 20 novel capsular polysaccharide loci (NCL) have been identified recently. However, information about pathogenic and antimicrobial resistance characteristics of strains carrying NCLs is still unavailable. In this study, we identified six new NCLs (designated as NCL21-26) from 35 non-typeable S.suis strains by agglutination tests and whole genome sequencing analysis. Further analysis of the genetic context of NCL25 and NCL26 showed a mosaic structure of the capsular polysaccharide loci. NCL25 exhibited considerable similarity to that of serotypes 10 and 11, and NCL26 shared similarity to that of serotype 9 and NCL4. Antimicrobial susceptibility testing demonstrated that strains carrying NCL21-26 were all resistant to clindamycin, lincomycin, erythromycin, tilmicosin and tetracycline. Animal infection experiments showed that the virulence of NCL26 strain NJ1112 isolated from a disease pig was similar to that of S.suis serotype 2 virulent strain SC070731 in both zebrafish and mouse infection models, highlighting the necessity for surveillance of strains belonging to NCL26. We also developed a multiplex PCR assay to detect NCL21-26 strains. Our findings expand the views of genetic diversity of S.suis capsular polysaccharide loci and S.suis pathogenic characteristic.

Serotyping and antimicrobial resistance of Mannheimia haemolytica strains from European cattle with bovine respiratory disease

The objective of this study was to assess the prevalence of three serotypes, A1, A2, and A6 in 98 M. haemolytica isolates collected from clinical BRD cases in European cattle and assess their antimicrobial resistance profiles. Isolates were characterized by serotyping (plate agglutination and serotype specific PCR) and antimicrobial susceptibility testing. The study identified a predominance of serotypes A1 (59%) and A6 (22%) in European M. haemolytica isolates exhibiting a relatively low level of antimicrobial resistance. A comprehensive understanding of the relative prevalence of different M. haemolytica serotypes in Europe informs a targeted approach for vaccine design against BRD.

Emergence of serotype 19A Streptococcus pneumoniae after PCV10 associated with a ST320 in adult population, in Porto Alegre, Brazil.

Use of pneumococcal conjugate vaccines has caused emergence of non-vaccine serotypes. No Brazilian data specifically about serotype 19A are available. We aimed to evaluate the frequency of occurrence, susceptibility profile and molecular epidemiology of serotype 19A before and after vaccine introduction in Brazil. Pneumococcal identification was performed by the conventional method. Strain serotype was determined by multiplex polymerase chain reaction (PCR) and/or Quellung reaction. Resistance was determined by Etest® and PCR was performed to determine the presence of macrolide resistance genes, ermB and/or mefA. Pneumococci were typed by Multilocus Sequence Typing. Thirty-eight serotype 19A Streptococcus pneumoniae were recovered, mostly from invasive diseases. Prevalence of serotype 19A increased following vaccination (from 3.5% before vaccination to 8.1% after, p = 0.04196). Non-susceptibility increased to most antimicrobials after vaccine introduction and was associated with clonal complex (CC)320. MLST showed nine different STs, which were grouped in one main CC: CC320 (63.9%). During the post-vaccination era, the frequency of this serotype increased significantly from 1.2% in 2011 to 18.5% in 2014 (p = 0.00001), with a concomitant decrease in the genetic variability: ST320 consistently predominated after vaccine-introduction (61.1%). Overall, our results showed a post-PCV10 increase in the frequency of serotype 19A. This was accompanied by a selection of CC320 and antimicrobial resistance.

A Compendium of Shigatoxigenic <i>Escherichia coli</i>: Origins, Bacteriological and Clinical Data on the Serogroups, Serotypes and Untypeable Strains of <i>E. coli</i> Reported between 1980 and 2017, Excluding O157:H7

The purpose of this paper was to create a compendium of serogroups, serotypes and untypeable strains of Shigatoxigenic/verotoxigenic (STEC/VTEC) Escherichia coli. The compendium includes the origins, bacteriological and clinical data on this important group of microbes. The collection of STEC/VTEC data extends from 1980 to 2017, and excludes STEC/VTEC O157:H7. A total of 499 papers were discovered and documented to create the compendium which includes all the serogroups and serotypes beginning with serogroup O1 through to serogroup O211 and includes O non-typeable strains and ill-defined strains including serotype O54071:H7. The paper summarises the findings of 8010 E. coli isolates and includes all details including source (human or animal), and clinical condition/disease, serogroup and serotypes, country of origin, year reported, and the author(s) with cited references. Some twenty clinical conditions were shown in association with 4320 serotypes/and untypeable strains. The compendium is a record of an important group of STEC/ VTEC and should provide a useful resource for both researchers and clinicians.

Antibody persistence and immune protection duration in turbot vaccinated by a Vibrio anguillarum inactivated bivalent vaccine based on O1 and O2 serotype strains

Antibody persistence and immune protection duration in turbot vaccinated by a <i>Vibrio anguillarum</i> inactivated bivalent vaccine based on O1 and O2 serotype strains

Bloodstream infections with Escherichia coli O16-ST131 and O25b-ST131: molecular epidemiology, phylogenetic analysis and antimicrobial resistance

To investigate the phylogenetics and prevalence of bloodstream infections with Escherichia coli ST131, the antimicrobial resistance profiles of the pathogens, and the clinical features. Non-duplicate Escherichia coli isolates were collected from 144 patients with bloodstream infections in our hospital between January and December, 2016.The phylogenetic groups of the isolates were analyzed using multiplex PCR, and O serotyping of ST131 strains was performed by allele-specific PCR.The clinical characteristics of the 144 patients were analyzed to define the differences in the clinical features between patients with ST131 infection and those with non-ST131 infection.Antibiotic susceptibility of the isolates was determined using the Vitek 2 compact system. The phylogenetic group analysis showed a domination by group B2 (41.0%[59/144]), followed by group F, group B1 and group E, which accounted for 16.7%(24/144), 13.9%(20/144), and 13.2% (19/144), respectively.Nine strains (6.3%) of Escherichia coli were identified to be ST131 strains, among which 8 were O25b-B2-ST131 strains and 1 was O16-B2-ST131 strain.Of the 9 cases of ST131 infection, 7(77.8%) were found to occur in a nosocomial setting.The demographic characteristics and clinical features of the ST131-infected patients were similar to those of non-ST131-infected patients.ST131 strains were sensitive to piperacillin/tazobactam, imipenem, ertapenem, and amikacin, but showed high resistance rates to cefazolin, ceftriaxone, ciprofloxacin, levofloxacin, gentamicin, and trimethoprim/ sulfamethoxazole (all over 50%).The positivity rate of ESBLs in the ST131 strains was 77.8%, and the multidrug resistance rate reached 88.9%, which was higher than that of non-ST131 isolates, but the difference was not statistically significant. The most common phylogenetic groups of Escherichia coli isolates from patients with bloodstream infections are group B2 and F, and the positivity rate of ST131 is low.We for the first time detected O16-ST131 in patients with blood-borne infections in China.The clinical features of ST131-infected patients are similar to those of non-ST131-infected patients.The positivity rate of ESBLs and the multidrug resistance rate are high in ST131 strains, which may raise concerns in the future.

Surveillance on susceptibility of strains isolated from pediatric infections.

During the period from January to December 2015, 104 Streptococcus pneumoniae strains, 129 Haemophilus influenzae strains and 54 Moraxella catarrhalis strains isolated from clinical specimens of pediatric infections in the national 16 institutions, studied susceptibilities of total 28 antibiotics, the capsular serotype for S.pneumoniae, the capsular b type and β-lactamase production capability for H.influenzae, and the β-lactamase production capability for M.catarrhalis were measured. In S.pneumoniae, the results showed that 68 strains (65.4%) were PSSP, 32 (30.8%) were PISP, and 4 (3.8%) were PRSP. The susceptibilities of TBPM and GRNX among oral antibiotics, and PAPM among injectable antibiotics demonstrated the lowest value with MIC90≤0.06μg/mL. The most frequent distribution of S.pneumoniae serotypes was seen in 15B, followed by 19A, and 35B. Serotype strains contained in 13-valent pneumococcal conjugate vaccine (PCV13) were 19 strains (18.3%). In H.influenzae, the results showed that BLNAS accounted for 40 strains (31.0%), BLNAI for 28 strains (21.7%), BLNAR for 47 strains (36.4%), β-lactamase producing for 14 strains (10.8%). The susceptibilities of quinolones demonstrated the lowest outcome among oral antibiotics with MIC90≤0.06μg/mL, and CTRX and TAZ/PIPC (TAZ4 fixed) among injectable antibiotics with MIC of 0.25μg/mL. There was no detection of capsular type b strains. In M.catarrhalis, all the isolates were β-lactamase producing strains. The susceptibilities of TBPM, CPFX, TFLX and GRNX among oral antibiotics, and TAZ/PIPC (TAZ4 fixed), PAPM, MEPM and DRPM among injectable antibiotics demonstrated the lowest outcome with MIC of ≤0.06μg/mL.

Innate Anti-microbial and Anti-chemotaxis Properties of Progranulin in an Acute Otitis Media Mouse Model.

Acute otitis media (AOM) is one of the most common infectious diseases primarily caused by Streptococcus pneumoniae (S.pn) among children. Progranulin (PGRN) is a multifunctional growth factor widely expressed in various tissues and cells. Studies have confirmed that PGRN is involved in the development of a variety of inflammatory diseases. We found that the expression of PGRN increased significantly in the middle ear of wild mice with AOM. However, its physiological functions in AOM still remain unknown. To examine the role of PGRN during AOM, we established an acute otitis media model in both C57BL/6 wild mice and PGRN-deficient (PGRN−/−) mice via transbullar injection with S.pn clinical strain serotype 19F. Interestingly, we observed dual results: on one hand, macrophage recruitment notably increased in PGRN−/− mice compared with WT mice; on the other hand, the overall bacterial clearance was surprisingly dampened in PGRN−/− mice. The enhanced recruitment of macrophages was associated with increased production of chemokine (C-C motif) ligand 2 (CCL2), while the decreased bacterial clearance was associated with impaired endocytosis capacity of macrophages. The scavenging ability of bacteria in PGRN−/− mice was recovered with administration of recombinant PGRN. These results suggested a novel dual role of PGRN in affecting the activities of macrophages.

Distribution of the pilS gene in Escherichia coli pathovars, its transfer ability and influence in the typical enteropathogenic E. coli adherence phenotype

Typical enteropathogenic Escherichia coli strains (tEPEC) cause attaching/effacing lesions in eukaryotic cells and produce the bundle-forming pilus (BFP), which interweaves and aggregates bacteria, resulting in the localized adherence (LA) pattern on eukaryotic cells. Previously, we identified tEPEC strains (serotype O119:H6) that exhibited LA simultaneously with an aggregative adherence (AA)-like pattern (LA/AA-like+). Remarkably, AA is characteristically produced by strains of enteroaggregative E. coli (EAEC), another diarrheagenic E. coli pathovar. In one LA/AA-like + strain (Ec404/03), we identified a conjugative plasmid containing the pil operon, which encodes the Pil fimbriae. Moreover, a pil operon associated with an AA pattern and plasmid transfer had been previously described in the EAEC C1096 strain. In this study, we investigated the occurrence of the two pilS alleles (pilSEc404 and pilSC1096) in tEPEC strains of different serotypes, origins and years of isolation. We also examined the potential relationship of pilS with the AA-like phenotype, its ability to be transferred by conjugation, and occurrence among strains of the other E. coli pathovars. The pilS alleles were found in 90 (55.2%) of 163 tEPEC strains, with pilSEc404 occurring more often (30.7%) than pilSC1096 (25.1%). About 21 tEPEC serotypes carried pilS. The pilS alleles were found in tEPEC strains from Chile, Peru and different Brazilian cities, with the oldest strain being isolated in 1966. No absolute correlation was found between the presence of pilS and the AA-like pattern. Conjugative pilS transfer was detected in 26.2% of pilSEc404+ strains and in 65.1% of pilSC1096+ strains, but only pilSEc404+ transconjugants were AA-like+, thus suggesting that the latter allele might need a different genetic background to express this phenotype. pilS was found in all other E. coli pathovars, where it was most prevalent in enterotoxigenic E. coli. More studies are needed to understand the mechanisms involved in the regulation of Pil expression and production.

Economic appraisal of vaccination against Streptoccocus agalactiae in Nile tilapia farms in Brazil

Infection with Streptococcus agalactiae causes mortality and major economic losses in Nile tilapia (Oreochromis niloticus) farming worldwide. In Brazil, serotype strains Ia, Ib and III have been isolated in streptococcosis outbreaks, but serotype Ib is the most prevalent. Vaccination is considered an effective method to prevent economically-important diseases in aquaculture and has been associated with decreased use of antibiotics and improvements in fish survival. We developed a flexible partial-budget model to undertake an economic appraisal of vaccination against Streptococcus agalactiae in Nile tilapia farmed in net cages in large reservoirs. The model considers the benefits and costs that are likely to be associated with vaccination at the farm-level, in one production cycle. We built three epidemiological scenarios of cumulative mortality attributable to S. agalactiae (5%, 10%, and 20%, per production cycle) in a non-vaccinated farm. For each scenario, we applied a stochastic model to simulate the net return of vaccination, given a combination of values of “vaccine efficacy”, “gain in feed conversion ratio”, “feed price”, “fish market price “, and “cost of vaccine dose”. In the 20% cumulative mortality scenario, the net return would break-even (benefits ≥ costs) in at least 97.9% of interactions. Should cumulative mortality be lower than 10%, the profitability of vaccination would be more dependent on better feed conversion ratio. The inputs “feed price” and “cost of vaccine” had minor effects on the output, in all pre-vaccination mortality scenarios. Although our simulations are based on conservative values and consider uncertainty about the modeled parameters, we conclude that vaccination against S. agalactiae is likely to be profitable in Nile tilapia farms, under similar production conditions.