Implications of <Emphasis Type="Italic">stx</Emphasis> loss for clinical diagnostics of Shiga toxin-producing <Emphasis Type="Italic">Escherichia coli</Emphasis>

The dynamics related to the loss of stx genes from Shiga toxin-producing Escherichia coli remain unclear. Current diagnostic procedures have shortcomings in the detection and identification of STEC. This is partly owing to the fact that stx genes may be lost during an infection or in the laboratory. The aim of the present study was to provide new insight into in vivo and in vitro stx loss in order to improve diagnostic procedures. Results from the study support the theory that loss of stx is a strain-related phenomenon and not induced by patient factors. It was observed that one strain could lose stx both in vivo and in vitro. Whole genome comparison of stx-positive and stx-negative isolates from the same patient revealed that different genomic rearrangements, such as complete or partial loss of the parent prophage, may be factors in the loss of stx. Of diagnostic interest, it was shown that patients can be co-infected with different E. coli pathotypes. Therefore, identification of eae-positive, but stx-negative isolates should not be interpreted as “Shiga toxin-lost” E. coli without further testing. Growth and recovery of STEC were supported by different selective agar media for different strains, arguing for inclusion of several media in STEC diagnostics.     

Clonal relationship between human and avian ciprofloxacin-resistant <Emphasis Type="Italic">Escherichia coli</Emphasis> isolates in North-Eastern Algeria

The objectives of this study were to determine rates, patterns, and mechanisms of antibiotic resistance, and to assess connections between chicken commensal, human commensal, and pathogenic ciprofloxacin-resistant Escherichia coli isolates. All E. coli isolates collected from chickens, their farmers, and patients in the Constantine region (North-east Algeria) were analyzed for bla and plasmid-mediated quinolone resistance (PMQR) gene contents, phylogroups, Rep-PCR profiles, and multilocus sequence types. A high prevalence of resistance to fluoroquinolones (51.4 % to ciprofloxacin) was recorded in avian isolates. Of these, 22.2 % carried the aac(6’)-Ib-cr gene, whereas lower resistance levels to these antibiotics were recorded in chicken farmers’ isolates. None of the commensal isolates harbored the qnr, qepA, or oqxAB genes. One human pathogenic isolate was ertapenem-resistant and harbored the bla _OXA-48 gene, 84 showed an extended-spectrum β-lactamase phenotype, with bla _CTX-M-15 gene prevalent in 87.2 % of them. Seventy isolates were resistant to fluoroquinolones, with aac(6’)-Ib-cr present in 72.8 %, qnrB in 5.7 %, and qnrS in 10 %. Three Rep-PCR profiles were common to chicken commensal and human pathogenic isolates (phylogroups D and B1; ST21, ST48, and ST471 respectively); one was found in both chicken and chicken-farmer commensal strains (D; ST108), while another profile was identified in a chicken-farmer commensal strain and a human pathogenic one (B1; ST19). These findings suggest clonal and epidemiologic links between chicken and human ciprofloxacin-resistant E. coli isolates and the important role that poultry may play in the epidemiology of human E. coli infections in the Constantine region.     

Characterization of carbapenem-resistant <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> from a healthcare region in Hong Kong

Carbapenem-resistant Enterobacteriaceae represents a major public health issue. This study investigated the clonality and resistance mechanisms of 92 carbapenem-resistant E. coli (n?=?21) and K. pneumoniae (n?=?71) isolates collected consecutively from clinical specimens and patients at high risk of carriage between 2010 and 2012 in a healthcare region in Hong Kong. Combined disk tests (CDTs) and the Carba NP test were used for phenotypic detection of carbapenemases. PCR assays were used to detect carbapenemase genes. All isolates were intermediate or resistant to at least one carbapenem. Nine (9.8 %) isolates were genotypic carbapenemase producers and included six K. pneumoniae (one ST1306/bla _IMP-4, one ST889/bla _IMP-4, two ST11/bla _KPC-2, one ST258/bla _KPC-2, one ST483/bla _NDM-1) and three E. coli (one ST131/bla _IMP-4, two ST744/ bla _NDM-1) isolates. All nine isolates carrying carbapenemase genes could be detected by the CDTs and the Carba NP test. PCR identified bla _CTX-M and bla _AmpC alone or in combination in 77.8 % (7/9) and 96.4 % (80/83) of the carbapenemase-producers and non-producers, respectively. Porin loss was detected in 22.2 % (2/9) and 59.0 % (49/83) of the carbapenemase-producers and non-producers, respectively. Overall, the E. coli clones were diverse (14 different STs), but 36.6 % (26/71) of the K. pneumoniae isolates belonged to ST11. In conclusion, the prevalence of carbapenemases among carbapenem-nonsusceptible E. coli and K. pneumoniae remained low in Hong Kong. Porin loss combined with AmpC and/or CTX-M type ESBL was the major mechanism of carbapenem resistance in the study population.     

Increasing incidence of carbapenemase-producing <Emphasis Type="Italic">Escherichia coli</Emphasis> and <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> in Belgian hospitals

Carbapenemase-producing Enterobacteriaceae are increasingly reported worldwide. The aim of the study was to determine the incidence and molecular epidemiology of carbapenemase-producing (CP) Escherichia coli and Klebsiella pneumoniae (CP-E/K) in Belgium. Eleven hospital-based laboratories collected carbapenem non-susceptible (CNS) isolates of E. coli and K. pneumoniae detected in clinical specimens from January 2013 to December 2014. All CNS strains were tested for carbapenemase production and typed by multilocus sequence typing (MLST) for a 6-month period as part of the European Survey on Carbapenemase-Producing Enterobacteriaceae in Europe (EuSCAPE) structured survey. In addition, an equal number of carbapenem-susceptible isolates collected were preserved as a control group for risk factor analysis. The overall incidence rate of CP-E/K isolates in hospitals increased from 0.124 in 2013 to 0.223 per 1000 admissions in 2014. From November 2013 to April 2014, 30 CP K. pneumoniae [OXA-48 (n?=?16), KPC (n?=?13), OXA-427 (n?=?1)] and five CP E. coli [OXA-48 (n?=?3), NDM (n?=?1), OXA-427 (n?=?1)] isolates were detected in ten hospitals. The 16 OXA-48-producing K. pneumoniae strains were distributed into eight sequence types (STs), while the 13 KPC-producing K. pneumoniae clustered into three STs dominated by ST512 (n?=?7) and ST101 (n?=?5). Compared to controls, we observed among CP-E/K carriers significantly higher proportion of males, respiratory origins, previous hospitalization, nosocomial setting, and a significantly lower proportion of bloodstream infections. Our study confirms the rapid spread of CP-E/K in Belgian hospitals and the urgent need for a well-structured and coordinated national surveillance plan in order to limit their dissemination.     

Morphological characterization and <Emphasis Type="Italic">HSP70</Emphasis>-, <Emphasis Type="Italic">IGS</Emphasis>-based phylogenetic analysis of two microsporidian parasites isolated from <Emphasis Type="Italic">Antheraea pernyi</Emphasis>

Two microsporidian isolates were extracted from single infected egg-laying tussah silk moth (Antheraea pernyi) in Liaoning Province, China. The microsporidia were subsequently grown in silk moth larvae, isolated, and subjected to morphological characterization (by light and transmission electron microscopy) and phylogenetic analysis (based on conserved genes). One type of spore was long-axis-oval in shape, measuring 4.71 × 1.95 μm, and the other type was short-axis-oval, measuring 3.64 × 2.17 μm. These dimensions were markedly different from those reported in the spores of the common microsporidia infecting A. pernyi, namely, Nosema pernyi (4.36 × 1.49 μm). A neighbor-joining phylogenetic tree based on HSP70 indicated that these microsporidia belonged to Nosema species and were closely related with Nosema bombycis and Nosema ceranae. Furthermore, in the phylogenetic tree based on the intergenic spacer (IGS) region, the long-axis-oval isolates were closely related and tended to form a clade away from the short-axis-oval isolates and N. pernyi isolates. The microsporidia isolated from A. pernyi clustered in one group. Nosema bombycis, Nosema spodopterae, and Endoreticulatus spp. appeared to be genetically distant from N. pernyi. The two isolates from A. pernyi fell in the Nosema group, but their spores differed from those of the spores of the common A. pernyi parasite N. pernyi, both in morphological and genetic aspects. The two isolates were designated Nosema sp. Ap (L) and Nosema sp. Ap (S). IGS was found to be informative in ascertaining phylogenetic relationships among species, and even closely related strains, of microsporidia.     

Isolation of <Emphasis Type="Italic">Pteropine orthoreovirus</Emphasis> from <Emphasis Type="Italic">Pteropus vampyrus</Emphasis> in Garut,Indonesia

Flying foxes belonging to the genus Pteropus are known to be reservoirs of zoonotic viruses. In this study, we describe the isolation of Pteropine orthoreovirus (PRV) from rectal swab samples of Pteropus vampyrus in Indonesia. PRV is an emerging zoonotic respiratory virus that can be transmitted from bats to humans. Rectal swabs (n?=?91) were screened by PCR for PRV and 10 (11%) were positive. Phylogenetic analysis based on nucleotide sequences indicated that the S2, S3, S4, M3, L2, and L3 segments of one isolate (Garut-69) were closely related to previously isolated strains in Indonesia. The remaining gene segments showed both similarity and genetic divergence with other PRV strains, suggesting that re-assortment events had occurred. This is the first report of PRV infection to P. vampyrus in West Java, Indonesia.     

The importance of <Emphasis Type="Italic">Helicobacter pylori tnpA</Emphasis>, <Emphasis Type="Italic">tnpB</Emphasis>, and <Emphasis Type="Italic">cagA</Emphasis> genes in various gastrointestinal diseases

The cag (cytotoxin-associated gene) pathogenicity island (cagPAI) is one of the major virulence determinants of Helicobacter pylori (H. pylori). The purpose of this study was to investigate the association of the three genes (tnpA, tnpB, and cagA) in H. pylori isolated from Azerbaijani patients with the different gastrointestinal disease. A total of 362 gastric biopsies were collected from hospitals of Tabriz University of Medical Sciences, and were cultured on Brucella agar. The tnpA, tnpB, and cagA genes were detected by PCR. Of the total 264 H. pylori isolates, tnpA, tnpB, and cagA genes were detected in 120 (45.5%), 56 (21.2%) and 172 (65.2%), respectively. A significant association between tnpA and tnpB genes and clinical outcomes were found (P < 0.05). The cagA status was not related to clinical outcomes in our subjects. The predominant genotype among cag-PAI is the cagA. The prevalence of tnpA, tnpB, and cagA genes are high in patients with gastric cancer, and a significant association is revealed between tnpA and tnpB with gastric cancer.     

Role of topoisomerase mutations,plasmid mediated resistance (<Emphasis Type="Italic">qnr</Emphasis>) and acrAB efflux pump in fluoroquinolone resistant clinical isolates of avian <Emphasis Type="Italic">Escherichia coli</Emphasis>

Introduction

We investigated the role of topoisomerase mutations, increased level of the multidrug efflux pump AcrAB, and the plasmid-borne genes (qnr) in the fluoroquinolone (FQ) resistant avian Escherichia coli simultaneously.

Material and method

Here, we used four FQs (ciprofloxacin, enrofloxacin, ofloxacin and pefloxacin) and eight clinical isolates of E. coli containing six fluoroquinolone-resistant and two fluoroquinolone- susceptible. PCR and direct sequencing methods were used to detect the role of regulator/ repressor gene (acrR).

Objective

The objective of this study was to determine the relationship of these resistance mechanisms for fluoroquinolone resistance.

Result

The results showed that (i) all four fluoroquinolone- resistant isolates have topoisomerase mutation and plasmid borne genes qnrS and aac(6')-Ib; (ii) three FQ (enrofloxacin, ofloxacin and pefloxacin) resistant isolates harboring qnrS genes; (iii) two FQ (ciprofloxacin and pefloxacin) resistant isolates had topoisomerase mutation and plasmid borne gene qnrS; (iv) all fluoroquinolone susceptible were not harboring qnrS gene and topoisomerase mutation (v) All isolates were negative for qnrA and qnrB.

Conclusion

We found that FQs resistance combination was correlated with synergistically contribution of these resistance mechanisms. Plasmid mediated resistance by qnrS was correlated to pefloxacin resistance but did not correlate to ofloxacin, enrofloxacin and ciprofloxacin. This mechanism might be account for the pefloxacin resistance in avian E. coli.

     

Structural organization of intact and damaged by <Emphasis Type="Italic">IS</Emphasis>100 element porin genes adjacent to the PGM region in <Emphasis Type="Italic">Yersinia pestis</Emphasis> and <Emphasis Type="Italic">Yersinia pseudotuberculosis</Emphasis> strains

The porin gene, which is adjacent to the pigmentation region (pgm), is usually damaged by IS100 element in highly virulent Yersinia pestis strains. In addition, the pgm region, which carries the genes responsible for virulence (high pathogenicity island) and biofilm generation (hms-operon), is flanked by direct IS100 copies (causing its destabilization). The study of distribution of intact and truncated porin genes was conducted among 240 Y. pestis strains from 39 natural foci of Russia and countries of the near abroad and 68 Yersinia pseudotuberculosis strains from different geographical regions. Most highly virulent Y. pestis strains and some phylogenetic Y. pseudotuberculosis lines of O:1 serotype contain truncated porin genes. At the same time, deletion of the pgm region by flanked IS100 in Y. pseudotuberculosis is impossible, since IS100 is integrated in the porin gene in an orientation opposite to that of Y. pestis. The intact porin gene is carried by all Y. pestis strains with low epidemic significance and certain phylogenetic lines of highly virulent Y. pestis strains from desert foci and Caspian sandy focus, as well as most Y. pseudotuberculosis strains of O:1 serotype. A continuous deletion, which includes the porin gene and a part of the astE gene, was detected in less virulent Y. pseudotuberculosis strains of O:3 serotype. The nucleotide sequence of porin genes is identical in Y. pestis and Y. pseudotuberculosis strains from different geographical regions. Three porin gene allele only differ by IS100 integration site and orientation or absence of its integration. The nucleotide sequence of IS100 introduced in the porin gene of Yersinia has small differences only for two Y. pestis strains isolated in America. The correlation of low frequency of Hms-mutants with the intact porin gene state in Y. pestis and the absence of such a correlation in Y. pseudotuberculosis were established.     

Development of <Emphasis Type="Italic">T</Emphasis><Subscript><Emphasis Type="Italic">m</Emphasis></Subscript>-shift genotyping method for detection of cat-derived <Emphasis Type="Italic">Giardia lamblia</Emphasis>

To develop T _m -shift genotyping method for detection of cat-derived Giardia lamblia, two sets of primers with two GC-rich tails of unequal length attached to their 5′-end were designed according to two SNPs (BG434 and BG170) of β-giardin (bg) gene, and specific PCR products were identified by inspection of a melting curve on real-time PCR thermocycler. A series of experiments on the stability, sensitivity, and accuracy of T _m -shift method was tested, and clinical samples were also detected. The results showed that two sets of primers based on SNP could distinguish accurately between assemblages A and F. Coefficient of variation of T _m values of assemblage A and F was 0.14 and 0.07% in BG434 and 0.10 and 0.11% in BG170, respectively. The lowest detection concentration was 4.52 × 10^?5 and 4.88 × 10^?5 ng/μL samples of assemblage A and F standard plasmids. The T _m -shift genotyping results of ten DNA samples from the cat-derived G. lamblia were consistent with their known genotypes. The detection rate of clinical samples by T _m -shift was higher than that by microscopy, and their genotyping results were in complete accordance with sequencing results. It is concluded that the T _m -shift genotyping method is rapid, specific, and sensitive and may provide a new technological mean for molecular detection and epidemiological investigation of the cat-derived G. lamblia.     

High frequency of occupied <Emphasis Type="Italic">attB</Emphasis> regions in Norwegian <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> isolates supports a two-step MRSA screening algorithm

Rapid nucleic acid amplification tests for methicillin-resistant Staphylococcus aureus (MRSA) diagnostics commonly target the mec resistance gene, genes specific for S. aureus, and the integration site for the SCCmec resistance cassette, orfX. Due to poor specificity when these target genes are used individually, additional culture is required to verify positive results. The combination of these targets is useful, but the optimal algorithm may depend on the presence of the genetic markers in S. aureus isolates, as well as the prevalence of MRSA in a population. The aim of the present study was to identify a rapid, low-cost, and functional screening algorithm in order to reduce the response time for MRSA diagnostics. An in-house orfX-SCCmec polymerase chain reaction (PCR) assay was established and evaluated. The results were compared with an existing mec/nuc PCR assay and traditional culture. Methicillin-sensitive S. aureus (MSSA) that tested false-positive in the orfX-SCCmec PCR assay were further investigated with full genome sequencing using the Ion PGM? System to verify results and causality. Based on these data, a two-step screening algorithm with initial mec/nuc PCR followed by orfX-SCCmec PCR on positive samples was suggested and tested on 1443 patient samples. 22.5 % of MSSA isolates tested false-positive with the orfX-SCCmec PCR. Full genome sequencing of these isolates identified genetic variation in the attB region of S. aureus, including empty cassette variants and non-mec SCC. The suggested two-step MRSA screening algorithm allowed us to report MRSA results for 95.6 % of all samples and 99 % of MRSA-negative samples after one day.     

Clinical and microbiological characteristics of peritoneal dialysis-related peritonitis caused by <Emphasis Type="Italic">Escherichia coli</Emphasis> in southern Taiwan

Peritonitis is a serious complication and major cause of treatment failure in patients undergoing peritoneal dialysis (PD). Escherichia coli is the major pathogen in extraintestinal Gram-negative infections, including PD-related peritonitis. The outcomes of E. coli peritonitis in PD varied from relatively favorable outcomes to a higher incidence of treatment failure. The aim of this study was to investigate the impact of bacterial virulence and host characteristics on the outcomes of PD-related peritonitis caused by E. coli. From January 2000 to June 2016, a total of 47 episodes of monomicrobial and 10 episodes of polymicrobial E. coli PD-related peritonitis, as well as 89 episodes of monomicrobial Gram-positive (56 Staphylococcus spp. and 33 Streptococcus spp.) PD-related peritonitis cases, were retrospectively enrolled. Clinical features, E. coli bacterial virulence, and outcomes were analyzed. Compared to Streptococcus spp. peritonitis, E. coli peritonitis had a higher peritoneal catheter removal rate (38 versus 12%; P =?0.0115). Compared to the monomicrobial group, patients in polymicrobial group were older and had higher peritoneal catheter removal rate (80 versus 38%; P =?0.0324). Treatment failure of E. coli peritonitis was associated with more polymicrobial peritonitis and immunocompromised comorbidity, longer duration of PD therapy, and more antimicrobial resistance. E. coli isolates with more iron-related genes had higher prevalence of phylogenetic group B2 and papG II, iha, ompT, and usp genes. This study demonstrates the important roles of clinical and bacterial characteristics in the outcomes of monomicrobial and polymicrobial E. coli PD-related peritonitis.     

Phylotyping and ColV plasmid-associated virulence genotyping of <Emphasis Type="Italic">E. coli</Emphasis> isolated from broiler chickens with colibacillosis in Iran

Avian pathogenic Escherichia coli (APEC) strains are responsible for significant losses to the poultry industry in many parts of the world. Although, many serotypes of E. coli are non pathogen, a relatively few number of serotypes carry virulence genes which make them damaging for chicken and other poultry. Previously, high prevalence of virulence genes carried on plasmid and/or chromosomal DNA has demonstrated in APECs obtained from different countries. The aim of the present study is characterization of E. coli isolated from broiler chickens with pericarditis and femoral head necrosis (FHN) associated with colibacillosis based on the phylogenetic typing and ColV plasmid-carried virulence genotyping. In present study, 290 E. coli isolates from pericardial sac (n?=?120) and lesions of femur (n?=?100) of chickens exhibiting clinical and necropsy findings of colibacillosis from poultry farms in Fars province, Iran, besides 70 isolates from the intestinal content of apparently healthy birds were phylotyped and examined for the presence of seven virulence genes (ompT, hly, iss, iutA, iron, tsh, and cvaC) carried on ColV plasmid by multiplex PCR. Phylotyping analysis showed that the most of the APEC isolates fell into the phylogenetic group A and subgroup A₁. Also, virulence genotyping indicated that ColV plasmid-carried virulence genes were significantly higher in APEC compared to avian fecal E. coli (AFEC). Based on the results of this study, having several virulence genes of ColV plasmid and belonging to the phylogenetic group A might provide useful characteristics for the better identifying Iranian APECs. However, the link between avian E. coli pathogenicity and different phylotypes and genotypes needs more future works involving a larger number of samples to be confirmed.     

Biofilm Forming Ability and <Emphasis Type="Italic">Spa</Emphasis> Gene Polymorphism in Methicillin Resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> Clinical Isolates in North of Iran

Spa typing has been shown to function as a genetic marker for Staphylococcus aureus outbreak investigations and epidemiological studies. This study was aimed to investigate biofilm formation capacity and spa gene polymorphism in methicillin resistant S. aureus (MRSA) strains isolated from clinical samples. A total of 102 S. aureus isolated during 2016, were analyzed for methicillin resistance and biofilm formation using phenotypic assays and PCR-based detection of associated genes. The polymorphic region of the spa gene was amplified by PCR using specific primers and subsequently in MRSA strains the amplified products were sequenced and spa types determined by using the spa database website. Out of 102 S. aureus, 41 isolates (40.2%) recognized as MRSA in phenotypic and genotypic investigations. In phenotypic assay, biofilm forming ability was detected in 71 isolates. The frequency of icaA and fnbA in test isolate were 53.9 and 65.7% respectively. Amplification of polymorphic region of the spa gene in all 102 tested isolates resulted in eight size fragments ranged between 168–336 bp. In MRSA strains thirteen distinct spa types with 5–12 repeats were observed. The most frequent types of spa were t030, t037, t325, t421, t937, t1814 and t084. spa types t2421, t1814, t359 and t2617 identified for the first time in Iran. The present results showed high biofilm formation capacity and great diversity of variable region of spa gene in MRSA strains and confirmed that, spa typing provides valuable information on the epidemiologic features and discrimination of this bacterium.     

<Emphasis Type="Italic">Mycoplasma hominis</Emphasis> and <Emphasis Type="Italic">Gardnerella vaginalis</Emphasis> display a significant synergistic relationship in bacterial vaginosis

Gardnerella vaginalis plays an important role in bacterial vaginosis (BV,) while the role of genital Mollicutes is less obvious. The diagnosis of BV by use of the current Gram stain Nugent score is also suboptimal for defining the role of Mollicutes that lack a cell wall. Since bacterial load and diversity is an important prerequisite for BV, real-time quantitative polymerase chain reaction (qPCR) assays enable these to be assessed. The purpose of this study was to define the role of genital Mollicutes and potential patterns of synergy with G. vaginalis in women with BV. Vaginal swabs from 130 women categorised by Nugent score as BV (n?=?28), intermediate (n?=?22) and non-BV (n?=?80) were tested against four qPCR TaqMan assays targeting G. vaginalis, Mycoplasma hominis, M. genitalium, Ureaplasma urealyticum and U. parvum. Statistical analyses were used to compare bacterial prevalence and load between the three groups of women. Mycoplasma hominis and G. vaginalis co-infection was significantly more common in BV (60.7 %) compared to intermediate (36.4 %) and non-BV (8.8 %) Nugent scores (p?<?0.001). Significantly higher loads of M. hominis (p?=?0.001) and G. vaginalis (p?<?0.001) were detected in women with BV and the respective loads in M. hominis and G. vaginalis co-infections displayed a significant positive correlation (p?<?0.001; r?=?0.60). No significant associations were seen with the other Mollicutes. The findings strengthen the evidence of a role for M. hominis in BV and a potential synergy with G. vaginalis. This synergy could be an important trigger of the condition and sexual contact the conduit for the transmission of an otherwise commensal bacterium that could initiate it.     

Low occurrence of the new species <Emphasis Type="Italic">Staphylococcus argenteus</Emphasis> in a <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> collection of human isolates from Belgium

Staphylococcus argenteus is a novel Staphylococcus species closely related to Staphylococcus aureus that has been recently described. In this study, we investigated the proportion and the characteristics of S. argenteus recovered from humans in Belgium. S. aureus. human isolates collected in Belgium from 2006 to 2015 (n?=?1,903) were retrospectively characterised via the presence of non-pigmented colonies on chocolate agar, spa typing and rpoB sequencing to determine if some of them were in fact S. argenteus. Out of 73 strains non-pigmented on chocolate plates, 3 isolates (0.16 %) showed rpoB sequences, in addition to spa and sequence types (ST2250/t5787, ST2250/t6675, ST3240/t6675), related to S. argenteus. Two of them were methicillin-resistant, harbouring a SCCmec type IV. The three S. argenteus isolates carried genes (sak, scn) of the immune evasion cluster. This first Belgian nationwide analysis showed a low occurrence of S. argenteus. Further studies should be conducted to identify the distribution range and the clinical impact of this new species.     

<Emphasis Type="Italic">Slc11a1</Emphasis> (<Emphasis Type="Italic">Nramp</Emphasis>-<Emphasis Type="Italic">1</Emphasis>) gene modulates immune-inflammation genes in macrophages during pristane-induced arthritis in mice

Objective and design

Pristane-induced arthritis (PIA) in AIRmax mice homozygous for Slc11a1 R and S alleles was used to characterize the influence of Slc11a1 gene polymorphism on immune responses during disease manifestation. Previous reports demonstrated that the presence of the Slc11a1 S allele increased the incidence and severity of PIA in AIRmax ^SS , suggesting that this gene could interact with inflammatory loci to modulate PIA. We investigated the effects of Slc11a1 alleles on the activation of phagocytes during PIA.

Treatment

Mice were injected intraperitoneally with two doses of 0.5 mL of mineral oil pristane at 60-day intervals. Arthritis development was accompanied for 180 days.

Results

AIRmax ^SS mice showed differential peritoneal macrophage gene expression profiles during PIA, with higher expression and production of H₂O₂, NO, IL-1β, IL-6, TNF-α, and several chemokines. The presence of the Slc11a1 R allele, on the other hand, diminished the intensity of macrophage activation, restricting arthritis development.

Conclusion

Our data demonstrated the fine-tuning roles of Slc11a1 alleles modulating macrophage activation, and consequent PIA susceptibility, in those mouse lines.

     

Prevalence and molecular diversity of invasive <Emphasis Type="Italic">Streptococcus dysgalactiae</Emphasis> and <Emphasis Type="Italic">Streptococcus pyogenes</Emphasis> in a German tertiary care medical centre

Prevalence of invasive ß-haemolytic streptococci (BHS) at a tertiary care hospital and molecular diversity of S. pyogenes and S. dysgalactiae was studied. Between 2012 and 2016, all blood culture sets (n?=?55,839), CSF (n?=?8413) and soft tissue (n = 20,926) samples were analysed for BHS positivity using HYBASE software. Molecular profiles of 99 S. pyogenes and S. dysgalactiae were identified by sequencing of M protein genes (emm types) and multiplex PCR typing of 20 other virulence determinants. Streptococci contributed to 6.2% of blood, 10.7% of CSF and 14.5% of soft tissue isolates, being among the most common invasive isolates. The overall rates of invasive S. pyogenes, S. agalactiae, S. dysgalactiae and S. pneumoniae were 2.4, 4.4, 2.1, and 5.3%. Whereas S. pneumoniae was 1.5% more common in CSF samples, BHS isolates were 2-fold and 11-fold higher in bacteraemia and invasive soft tissue infections. Genetic BHS typing revealed wide molecular diversity of invasive and noninvasive group A and group G BHS, whereas one emm-type (stG62647.0) and no other virulence determinants except scpA were detected in invasive group C BHS. BHS were important invasive pathogens, outpacing S. pneumoniae in bacteraemia and invasive soft tissue infections. The incidence of S. dysgalactiae infections was comparable to that of S. pyogenes even with less diversity of molecular virulence. The results of this study emphasise the need for awareness of BHS invasiveness in humans and the need to develop BHS prevention strategies.     

Incidence of antibiotic resistance and virulence determinants in <Emphasis Type="Italic">Enterococcus faecium</Emphasis> and <Emphasis Type="Italic">Enterococcus faecalis</Emphasis> strains,isolated from traditional cheeses in Turkey

Enterococcus faecalis (n = 15) and Enterococcus faecium (n = 33) strains isolated from traditional Turkish cheeses were tested for susceptibility to 11 different antimicrobial agents and for the presence of selected genes encoding resistance and 13 genes encoding virulence factors using PCR. Furthermore, the plasmid profile of enterococci was examined. All E. faecium and E. faecalis isolates were resistant to nalidixic acid and kanamycin. The percentages of other resistant E. faecium and E. faecalis isolates, respectively, were 97 and 100% to streptomycin, 15.1 and 20% to ampicillin, 9.1 and 26.7% to gentamycin, 12.1 and 46.6% to chloramphenicol, 12.1 and 60% to tetracycline, 75.7 and 93.3% to rifampicin, 84.8 and 80% to vancomycin, 97 and 100% to erytromycin and 72.7 and 60% to ciprofloxacin. efaA _fm (100%) and ccf (90.1%) genes were the most common virulence genes identified among E. faecium isolates while efaA _fs (100%), cpd (100%), ccf (93.3%) and cob (86.7%) genes among E. faecalis isolates. Cytolysin determinants (cylM, cylB, cylA) were not detected among tested strains. Plasmid profile analysis of Enterococcus spp. revealed plasmid DNA bands ranging in size from 2.4 to 35.8 kb.