Sequence Type 131 Research Articles

Molecular Characteristics of NDM-5-Producing Escherichia coli from a Cat and a Dog in South Korea.

Carbapenemase-producing Enterobacteriaceae (CPE) have been very rarely reported in companion animals in South Korea. In this study, we aimed to investigate the molecular characteristics and relatedness of two New Delhi metallo-β-lactamase (NDM-5)-producing Escherichia coli isolates from rectal swabs of a dog and a cat hospitalized in different veterinary hospitals in South Korea during 2019. Antimicrobial susceptibility was tested by the Etest and broth microdilution method. PCR and sequencing were performed to detect antimicrobial resistance genes. Plasmid replicon typing and Southern blotting hybridization were performed to determine the replication origin of the plasmid and location of the blaNDM-5 gene, respectively. Their macrorestriction profiles for E. coli isolates were assessed by multilocus sequence typing (MLST) and pulse-field gel electrophoresis (PFGE). The two carbapenem-resistant E. coli isolates harbored the blaNDM-5 gene located on the IncX3 plasmid. Allele sequence analysis for MLST showed that the two E. coli isolates were attributed to sequence type 410 (ST410). The NDM-5-producing E. coli isolate from the cat presented high clonal similarity (94%) assessed by PFGE to a previously reported NDM-5-producing E. coli ST410 isolate from a dog hospitalized in the same hospital in 2017. The two E. coli isolates for the genetic environment surrounding the blaNDM-5 gene had the same structure: ISAba125-blaNDM-5-bleMBL-trpF-TAT-ISCR26. This study revealed a direct transmission of the NDM-5-producing E. coli ST410 isolate between a dog and a cat. This is the first report of NDM-5 carbapenemase-producing E. coli isolate from a cat in South Korea.

A Comprehensive Account of Escherichia coli Sequence Type 131 in Wastewater Reveals an Abundance of Fluoroquinolone-Resistant Clade A Strains.

In the ten years since its discovery, the Escherichia coli clone sequence type 131 (ST131) has become a major international health threat, with the multidrug-resistant and extended-spectrum β-lactamase (ESBL)-producing clade C emerging as the globally dominant form. ST131 has previously been isolated from wastewater; however, most of these studies selectively screened for ESBL-producing organisms, thereby missing the majority of remaining ST131 clades. In this study, we used a high-throughput PCR-based screening strategy to comprehensively examine wastewater for the presence of ST131 over a 1-year period. Additional multiplex PCRs were used to differentiate clades and obtain an unbiased account of the total ST131 population structure within the collection. Furthermore, antimicrobial susceptibility profiles of all ST131-positive samples were tested against a range of commonly used antibiotics. From a total of over 3,762 E. coli wastewater samples, 1.86% (n = 70) tested positive for ST131, with the majority being clade A isolates. In total, 63% (n = 44) were clade A, 29% (n = 20) were clade B, 1% (n = 1) were clade C0, 6% (n = 4) were clade C1, and 1% (n = 1) were clade C2. In addition, a very high rate of resistance to commonly used antibiotics among wastewater isolates is reported, with 72.7% (n = 32) of clade A resistant to ciprofloxacin and high rates of resistance to gentamicin, sulfamethoxazole-trimethoprim, and tetracycline in clades that are typically sensitive to antibiotics.IMPORTANCE ST131 is a global pathogen. This clone causes urinary tract infections and is frequently isolated from human sources. However, little is known about ST131 from environmental sources. With the widely reported increase in antibiotic concentrations found in wastewater, there is additional selection pressure for the emergence of antibiotic-resistant ST131 in this niche. The unbiased screening approach reported herein revealed that previously antibiotic-sensitive lineages of ST131 are now resistant to commonly used antibiotics present in wastewater systems and may be capable of surviving UV sterilization. This is the most comprehensive account of ST131 in the wastewater niche to date and an important step in better understanding the ecology of this global pathogen.

Effect of ramR loss-of-function insertion on tigecycline resistance in clinical isolates of carbapenem-resistant Klebsiella pneumoniae

ObjectivesTigecycline is an antibacterial agent restricted for use against carbapenem-resistant Klebsiella pneumoniae (CRKP). This study aimed to identify the tigecycline resistance mechanism in clinical CRKP isolates obtained from a 60-year-old femalepatient during tigecycline treatment. MethodsThree K. pneumoniae isolates obtained during tigecycline treatment were subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, and whole-genome sequencing and analysis. The function of ramR was confirmed by gene complementation. ResultsThree K. pneumoniae isolates (W814, W112 and W113) were collected from the patient on Days 0, 10 and 13, respectively, of ongoing tigecycline treatment. Antimicrobial susceptibility testing showed resistance to all antibiotics except tigecycline and ceftazidime/avibactam. The tigecycline minimum inhibitory concentration (MIC) for strains W814 and W112 was 4 mg/L compared with 16 mg/L for strain W113. The three strains belonged to sequence type 11 (ST11) and had a similar PGFE pattern. Insertion sequence (IS) element ISKpn18 in ramR was identified in strain W113. A parent strain transformed with plasmid pCR2.1-Hyg carrying ramR enhanced tigecycline susceptibility, thus confirming that a loss-of-function insertion in ramR contributes to tigecycline resistance. ConclusionISKpn18 insertion in the ramR gene contributes to the tigecycline resistance mechanism in the isolated K. pneumoniae strains.

Increased intracellular survival of Salmonella Typhimurium ST313 in HIV-1-infected primary human macrophages is not associated with Salmonella hijacking the HIV compartment.

Non-typhoidal Salmonella (NTS) causes a severe invasive syndrome (iNTS disease) described in HIV-positive adults. The impact of HIV-1 on Salmonella pathogenesis and the molecular basis for the differences between these bacteria and classical diarrhoeal S. Typhimurium remains unclear. Here, we show that iNTS-associated S. Typhimurium Sequence Type 313 (ST313) bacteria show greater intracellular survival in primary human macrophages, compared with a 'classical' diarrhoeal S. Typhimurium ST19 isolate. The increased intracellular survival phenotype of ST313 is more pronounced in HIV-infected macrophages. We explored the possibility that the bacteria take advantage of the HIV-associated viral-containing compartments created in human macrophages that have low pH. Confocal fluorescence microscopy and focussed ion beam-scanning electron microscopy tomography showed that Salmonella did not co-localise extensively with HIV-positive compartments. The capacity of ST313 bacteria to survive better than ST19 bacteria within primary human macrophages is enhanced in cells pre-infected with HIV-1. Our results indicate that the ST313 bacteria do not directly benefit from the niche created by the virus in HIV-1-infected macrophages, and that they might take advantage from a more globally modified host cell. A better understanding of the interplay between HIV-1 and Salmonella is important not only for these bacteria but also for other opportunistic pathogens.

Listeriosis Outbreak in South Africa: A Comparative Analysis with Previously Reported Cases Worldwide.

Listeria species are Gram-positive, rod-shaped, facultative anaerobic bacteria, which do not produce endospores. The genus, Listeria, currently comprises 17 characterised species of which only two (L. monocytogenes and L. ivanovii) are known to be pathogenic to humans. Food products and related processing environments are commonly contaminated with pathogenic species. Outbreaks and sporadic cases of human infections resulted in considerable economic loss. South Africa witnessed the world’s largest listeriosis outbreak, characterised by a progressive increase in cases of the disease from January 2017 to July 2018. Of the 1060 laboratory-confirmed cases of listeriosis reported by the National Institute of Communicable Diseases (NICD), 216 deaths were recorded. Epidemiological investigations indicated that ready-to-eat processed meat products from a food production facility contaminated with L. monocytogenes was responsible for the outbreak. Multilocus sequence typing (MLST) revealed that a large proportion (91%) of the isolates from patients were sequence type 6 (ST6). Recent studies revealed a recurrent occurrence of small outbreaks of listeriosis with more severe side-effects in humans. This review provides a comparative analysis of a recently reported and most severe outbreak of listeriosis in South Africa, with those previously encountered in other countries worldwide. The review focuses on the transmission of the pathogen, clinical symptoms of the disease and its pathogenicity. The review also focuses on the major outbreaks of listeriosis reported in different parts of the world, sources of contamination, morbidity, and mortality rates as well as cost implications. Based on data generated during the outbreak of the disease in South Africa, listeriosis was added to the South African list of mandatory notifiable medical conditions. Surveillance systems were strengthened in the South African food chain in order to assist in preventing and facilitating early detection of both sporadic cases and outbreaks of infections caused by these pathogens in humans.

Proteogenomic analysis of the Clostridium difficile exoproteome reveals a correlation between phylogenetic distribution and virulence potential

C. difficile induces antibiotic-associated diarrhea due to the action of two secreted toxins, TcdA and TcdB. A considerable range of virulence among C. difficile strains has been widely reported. During a hospital outbreak, 46 isolates were collected that belonged to different genotypes. Of those, the majority corresponded to two virulent strains, the globally distributed Sequence Type 1 (ST1)_North American Pulsotype 1 (NAP1) and the endemic ST54_NAPCR1 genotypes, respectively. Whereas the virulence of the latter has been attributed to increased secretion of toxins and production of a highly cytotoxic TcdB, these characteristics do not explain the increased lethality of the former. We undertook a proteomic comparative approach of the isolates participating in the outbreak to look for proteins present in the exoproteome of the ST1_NAP1and ST54_NAPCR1 strains. We used a low virulent ST2_NAP4 strain isolated also in the outbreak as control. Dendrograms constructed using the exoproteomes of the strains were very similar to those created using genomic information, suggesting an association between secreted proteins and relative virulence of the strains. By 2D electrophoresis and mass spectrometry it was found that approximately half of the proteins are shared among strains of different genotypes. From the identified proteins, the surface-located SlpA draw our attention due to its detection in ST54_NAPCR1 exoproteomes. Biochemical analysis indicated that the processing of SlpA is different in the ST54_NAPCR1 strain and confirmed that this strain secretes more SlpA than its counterparts. Furthermore, SlpA from the ST54_NAPCR1 strain exerted an increased proinflammatory activity. Altogether, these results indicate that the exoproteome composition correlates with the C. difficile genotype and suggest that particular proteins secreted by some strains could synergize with the effects of TcdA and TcdB increasing their virulence.

Environmental Presence and Genetic Characteristics of Carbapenemase-Producing Enterobacteriaceae from Hospital Sewage and River Water in the Philippines.

This study aimed to evaluate the prevalence and genetic characteristics of carbapenemase-producing Enterobacteriaceae (CPE) in hospital sewage and river water in the Philippines, which has a typical tropical maritime climate. We collected 83 water samples from 7 hospital sewage and 10 river water sites. CPE were identified using CHROMagar mSuperCARBA, and Gram-negative strains were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) or 16S rRNA gene sequencing. Resistance genes in Enterobacteriaceae strains were identified using PCR and DNA sequencing, and transferability of carbapenemase genes from the CPE was investigated with conjugation experiments. Genotyping was performed using multilocus sequence typing (MLST) for Escherichia coli and Klebsiella pneumoniae Out of 124 Enterobacteriaceae isolates, we identified 51 strains as CPE and divided these into 7 species, 11 E. coli, 14 Klebsiella spp., 15 Enterobacter spp., and 11 others, including 4 additional species. Conjugation experiments via broth mating and using E. coli J53 revealed that 24 isolates can transfer carbapenemase-encoding plasmids. MLST analysis showed that 6 of 11 E. coli isolates belonged to clonal complex 10 (CC10). Of 11 K. pneumoniae strains, 9 unique sequence types (STs) were identified, including ST147. Five types of carbapenemase genes were identified, with the most prevalent being NDM (n = 39), which is epidemic in clinical settings in the Philippines. E. coli CC10 and K. pneumoniae ST147, which are often detected in clinical settings, were the dominant strains. In summary, our results indicate that hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.IMPORTANCE Carbapenemase-producing Enterobacteriaceae (CPE) cause severe health care-associated infections, and their increasing prevalence is a serious concern. Recently, natural ecosystems have been recognized as important reservoirs of antibiotic resistance genes. We investigated the prevalence and genetic characteristics of CPE isolated from the environment (hospital sewage and river water) in the Philippines and found several CPE, including Escherichia coli and other species, with different carbapenemases. The most prevalent carbapenemase gene type was NDM, which is endemic in clinical settings. This study revealed that isolates belonging to carbapenemase-producing E. coli CC10 and K. pneumoniae sequence type 147 (ST147), which are often detected in clinical settings, were dominant in the natural environment. Our work here provides a report on the presence and characteristics of CPE in the environment in the Philippines and demonstrates that both hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.

Allelic profile of Serbian Xanthomonas campestris pv. campestris isolates from cabbage

Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease of cabbage (Brassica oleracea var. capitata L.), is one of the most important bacteria which affect proper cabbage growth, leading to head weight and quality losses and thereby drastically reducing its marketing value. The pathogen is genetically diverse, which is evident from the presence of eleven races worldwide and more than thirty combinations of allelic profiles. Therefore, this study aimed to determine the allelic profiles of Serbian cabbage Xcc strains obtained in 2014. The analysis was done on three selected Xcc strains whose DNA was first amplified using polymerase chain reaction (PCR) with four housekeeping genes - P-XdnaK, fyuA, gyrB, and rpoD, then sequenced, and the obtained sequences were finally used to determine allelic profiles. Allelic profiles were determined by comparison with 33 Xcc strains obtained from different hosts and regions, whose allelic profiles had been determined previously. A non-redundant database (NRDB) from the pubMLST was used for allelic profile determination and Phyloviz software for constructing a minimum spanning tree. The obtained allelic profile of all Serbian Xcc cabbage strains was 1, 3, 1, 1 for the P-X-dnaK, fyuA, gyrB and rpoD genes, respectively. This profile is assigned as sequence type 2 (ST2) and it coincides with a Portuguese B. oleracea Xcc strain, CPBF 213, originating from B. oleracea var. costata. No connection between sequence type (ST) and the host was detected.

Late onset group B streptococcus disease manifesting as acute suppurative parotitis

Few patients with acute suppurative parotitis (ASP) due to group B streptococcus (GBS) have been documented. Limited data on clinical and microbiological features and infectious route are available. We present a 21-day-old boy with invasive GBS disease manifesting as ASP. The patient was admitted because of irritability, fever, and erythematous swelling over the right parotid area. No purulent material exuded from the Stensen's duct. Ultrasonography and computed tomography of the neck showed findings indicative of ASP. On the day after admission, blood culture yielded GBS. The isolate was determined as GBS serotype Ia and sequence type-23, and the patient was successfully treated with intravenous ampicillin for 10 days. A review of the literature revealed 11 GBS ASP infants including ours with age at onset between 13 days and 12 weeks. All infants had bacteremia while pus from the Stensen's duct was detected in only one case. This finding remarkably contrasts with ASP caused by pathogens other than GBS, where the infection usually spreads via a retrograde route from Stensen's duct. The present case and literature review indicate GBS ASP primarily arises from bloodstream infection, and that ASP should be included in an infectious focus as late onset GBS disease.

Large Fecal Reservoir of Escherichia coli Sequence Type 131-H30 Subclone Strains That Are Shared Within Households and Resemble Clinical ST131-H30 Isolates.

Emerging antimicrobial-resistant Escherichia coli represent mainly the nested (fluoroquinolone-resistant [FQR]) H30R and H30Rx subclones within sequence type 131 (ST131). Intestinal colonization and within-household transmission may underlie H30R's emergence. We screened fecal samples from 741 volunteers (383 veterans, 358 household members, including pets) for ST131 and FQR E. coli (FQREC) and used molecular profiling to resolve unique strains. Selected strains underwent PCR-based detection of phylogroups, sequence types (STs), H30, H30Rx, and 53 virulence genes (VGs). Within-household strain sharing was compared with household, host, and bacterial characteristics. Fecal isolates were compared with clinical isolates. Colonization prevalence was 5.1% for H30R, 8% for ST131 (67% FQREC), and 10% for FQREC (52% ST131). ST131 isolates exhibited more VGs than non-ST131 isolates. Strain sharing (27% of multisubject households, 18% of corresponding subjects) was associated with the elderly, FQREC, H30R, H30Rx, ST73, and specific VGs. Fecal ST131 and FQREC isolates resembled contemporaneous and historical clinical isolates according to all studied traits. Veterans and their human household members commonly carry and extensively share FQREC, predominantly H30R, thereby likely facilitating the ST131 pandemic. Strain sharing corresponds with multiple bacterial characteristics, including FQ resistance and specific VGs, which may promote intestinal colonization and/or host-to-host transmission.

Determinants of Group B streptococcal virulence potential amongst vaginal clinical isolates from pregnant women.

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a Gram-positive bacterium isolated from the vaginal tract of approximately 25% of women. GBS colonization of the female reproductive tract is of particular concern during pregnancy as the bacteria can invade gestational tissues or be transmitted to the newborn during passage through the birth canal. Infection of the neonate can result in life-threatening pneumonia, sepsis and meningitis. Thus, surveillance of GBS strains and corresponding virulence potential during colonization is warranted. Here we describe a panel of GBS isolates from the vaginal tracts of a cohort of pregnant women in Michigan, USA. We determined that capsular serotypes III and V were the most abundant across the strain panel, with only one isolate belonging to serotype IV. Further, 12.8% of strains belonged to the hyper-virulent serotype III, sequence type 17 (ST-17) and 15.4% expressed the serine rich repeat glycoprotein-encoding gene srr2. Functional assessment of the colonizing isolates revealed that almost all strains exhibited some level of β-hemolytic activity and that ST-17 strains, which express Srr2, exhibited increased bacterial adherence to vaginal epithelium. Finally, analysis of strain antibiotic susceptibility revealed the presence of antibiotic resistance to penicillin (15.4%), clindamycin (30.8%), erythromycin (43.6%), vancomycin (30.8%), and tetracycline (94.9%), which has significant implications for treatment options. Collectively, these data provide important information on vaginal GBS carriage isolate virulence potential and highlight the value of continued surveillance.

Vaccine Protection against Multidrug-Resistant Klebsiella pneumoniae in a Nonhuman Primate Model of Severe Lower Respiratory Tract Infection.

Klebsiella pneumoniae is a human gut communal organism and notorious opportunistic pathogen. The relative high burden of asymptomatic colonization by K. pneumoniae is often compounded by multidrug resistance-a potential problem for individuals with significant comorbidities or other risk factors for infection. A carbapenem-resistant K. pneumoniae strain classified as multilocus sequence type 258 (ST258) is widespread in the United States and is usually multidrug resistant. Thus, treatment of ST258 infections is often difficult. Inasmuch as new preventive and/or therapeutic measures are needed for treatment of such infections, we developed an ST258 pneumonia model in cynomolgus macaques and tested the ability of an ST258 capsule polysaccharide type 2 (CPS2) vaccine to moderate disease severity. Compared with sham-vaccinated animals, those vaccinated with ST258 CPS2 had significantly less disease as assessed by radiography 24 h after intrabronchial installation of 108 CFU of ST258. All macaques vaccinated with CPS2 ultimately developed ST258-specific antibodies that significantly enhanced serum bactericidal activity and killing of ST258 by macaque neutrophils ex vivo Consistent with a protective immune response to CPS2, transcripts encoding inflammatory mediators were increased in infected lung tissues obtained from CPS-vaccinated animals compared with control, sham-vaccinated macaques. Taken together, our data provide support for the idea that vaccination with ST258 CPS can be used to prevent or moderate infections caused by ST258. As with studies performed decades earlier, we propose that this prime-boost vaccination approach can be extended to include multiple capsule types.IMPORTANCE Multidrug-resistant bacteria continue to be a major problem worldwide, especially among individuals with significant comorbidities and other risk factors for infection. K. pneumoniae is among the leading causes of health care-associated infections, and the organism is often resistant to multiple classes of antibiotics. A carbapenem-resistant K. pneumoniae strain known as multilocus sequence type 258 (ST258) is the predominant carbapenem-resistant Enterobacteriaceae in the health care setting in the United States. Infections caused by ST258 are often difficult to treat and new prophylactic measures and therapeutic approaches are needed. To that end, we developed a lower respiratory tract infection model in cynomolgus macaques in which to test the ability of ST258 CPS to protect against severe ST258 infection.

Draft Genome Sequence of an Escherichia coli Sequence Type 410 Isolate Harboring bla NDM-5 Genes with gyrA and parE Mutations, Isolated from Urine Culture in China.

Escherichia coli sequence type 410 (ST410) is now an international high-risk clone and is responsible for a large number of clinical infections. Here, we report the draft genome sequence of an ST410 clinical isolate harboring multiple bla NDM-5 genes that was obtained from urine culture in China.

Sequence type-258 carbapenem-resistant Klebsiella pneumoniae isolates in which ceftazidime–avibactam resistance emerged are not hypermutators

Ceftazidime–avibactam resistance among carbapenem-resistant Klebsiella pneumoniae at our hospital has emerged in sequence type (ST)-258, clade II isolates. We investigated hypermutability of ST258, clade II (n = 6) and clade I K. pneumoniae (n = 8) using a standard rifampin assay. Mutational frequencies were ≤10–7.1, indicating that isolates were not hypermutators. Mutational frequencies did not differ between clade II and I isolates. Ceftazidime–avibactam resistance among ST258, clade II K. pneumoniae is most likely a reflection of our hospital's ecology.

Characterization of Klebsiella pneumoniae ST11 Isolates and Their Interactions with Lytic Phages

The bacterial pathogen Klebsiella pneumoniae causes urinary tract infections in immunocompromised patients. Generally, the overuse of antibiotics contributes to the potential development and the spread of antibiotic resistance. In fact, certain strains of K. pneumoniae are becoming increasingly resistant to antibiotics, making infection by these strains more difficult to treat. The use of bacteriophages to control pathogens may offer a non-antibiotic-based approach to treat multidrug-resistant (MDR) infections. However, a detailed understanding of phage–host interactions is crucial in order to explore the potential success of phage-therapy for treatment. In this study, we investigated the molecular epidemiology of nine carbapenemase-producing K. pneumoniae isolates from a local hospital in Shanghai, China. All strain isolates belong to sequence type 11 (ST11) and harbor the blaKPC-2 gene. The S1-PFGE (S1 nuclease pulsed field gel electrophoresis) pattern of the isolates did not show any relationship to the multilocus sequence typing (MLST) profiles. In addition, we characterized phage 117 and phage 31 and assessed the potential application of phage therapy in treating K. pneumoniae infections in vitro. The results of morphological and genomic analyses suggested that both phages are affiliated to the T7 virus genus of the Podoviridae family. We also explored phage–host interactions during growth in both planktonic cells and biofilms. The phages’ heterogeneous lytic capacities against K. pneumoniae strains were demonstrated experimentally. Subsequent culture and urine experiments with phage 117 and host Kp36 initially demonstrated a strong lytic activity of the phages. However, rapid regrowth was observed following the initial lysis which suggests that phage resistant mutants were selected in the host populations. Additionally, a phage cocktail (117 + 31) was prepared and investigated for antimicrobial activity. In Luria Broth (LB) cultures, we observed that the cocktail showed significantly higher antimicrobial activity than phage 117 alone, but this was not observed in urine samples. Together, the results demonstrate the potential therapeutic value of phages in treating K. pneumoniae urinary tract infections.

Whole genome sequence of an Escherichia coli ST410 isolate co-harbouring blaNDM-5, blaOXA-1, blaCTX-M-15, blaCMY-2, aac(3)-IIa and aac(6')-Ib-cr genes isolated from a patient with bloodstream infection in China.

Mortality associated with carbapenemase-producing Enterobacteriaceae is high as there are few therapeutic options. Escherichia coli sequence type 410 (ST410) is currently an international high-risk clone and is responsible for a large number of clinical infections. Here we report the draft genome sequence of a ST410 clinical E. coli isolate (ECS9) co-harbouring blaNDM-5, blaOXA-1, blaCTX-M-15, blaCMY-2, aac(3)-IIa and aac(6')-Ib-cr genes, obtained from a patient with bloodstream infection in China. The genome of E. coli ECS9 was sequenced using an Illumina HiSeqTM 4000 instrument with a 150-bp paired-end approach. Generated sequence reads were assembled using Velvet 1.2.10. Contigs were annotated using Rapid Annotation using Subsystem Technology (RAST), and further whole-genome sequence data analyses were performed. Escherichia coli ECS9 belongs to multilocus sequence typing (MLST) ST410. The total number of assembled bases was 4 935 145 bp, with 5077 protein-coding sequences. The presence of the blaNDM-5, blaOXA-1, blaCTX-M-15 and blaCMY-2 genes was detected in addition to other antimicrobial resistance genes conferring resistance to fluoroquinolones, aminoglycosides, trimethoprim, sulfonamides and tetracyclines. To our knowledge, this is the first report of anE. coli ST410 strain co-harbouring blaNDM-5, blaOXA-1, blaCTX-M-15, blaCMY-2, aac(3)-IIa and aac(6')-Ib-cr, obtained from a bloodstream infection in China. The presented genome sequence of carbapenemase-producing E. coli strain ST410 could provide further insight into the acquisition of multiple resistance genes by this successful lineage.

Neisseria meningitidis Serogroup W Meningitis Epidemic in Togo, 2016.

BackgroundDuring 2014, 4 regions in Togo within the African meningitis belt implemented vaccination campaigns with meningococcal serogroup A conjugate vaccine (MACV). From January to July 2016, Togo experienced its first major Neisseria meningitidis serogroup W (NmW) outbreak. We describe the epidemiology, response, and management of the outbreak.MethodsSuspected, probable, and confirmed cases were identified using World Health Organization case definitions. Through case-based surveillance, epidemiologic and laboratory data were collected for each case. Cerebrospinal fluid specimens were analyzed by polymerase chain reaction, culture, or latex agglutination. Vaccination campaigns were conducted in affected districts.ResultsFrom January 11 to July 5, 2016, 1995 suspected meningitis cases were reported, with 128 deaths. Among them, 479 (24.0%) were confirmed by laboratory testing, and 94 (4.7%) and 1422 (71.3%) remained as probable and suspected cases, respectively. Seven epidemic districts had cumulative attack rates greater than 100 per 100 000 population. Of the confirmed cases, 91.5% were NmW; 39 of 40 available NmW isolates were sequence type-11/clonal complex-11.ConclusionsThis outbreak demonstrates that, although high coverage with MACV has reduced serogroup A outbreaks, large meningococcal meningitis outbreaks due to other serogroups may continue to occur; effective multivalent meningococcal conjugate vaccines could improve meningococcal disease prevention within meningitis belt populations.

Clinical and molecular characterization of both methicillin-resistant andsensitive staphylococcus aureus mastitis

This study targeted bovine mastitis as a possible source of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA), to identify clinical signs associated with MRSA- and non-MRSA-associated mastitis. Thirty-eight mastitis cases (68 infected quarters) were investigated. Gram-positive cocci-shaped isolates were selected based on Baird Parker agar growth as well as Gram-stained bacterial smears. Molecular screening for Staphylococcus aureus (S. aureus) yielded 17 isolates, of which five (29.41%) were methicillin resistant. The five isolates were mecA positive, but mecC negative. Multilocus sequence typing (MLST) indicated that sequence type 1 (ST1) was the identified type of all isolates of MRSA. S. aureus-associated cases showed different clinical forms of mastitis, including subclinical, acute, chronic, and gangrenous. Additionally, subclinical mastitis was the only detected condition associated with MRSA, which may represent a potential hidden risk for humans. Phenotypically, isolates of MRSA showed resistance to all of the tested β-lactam antimicrobials, with marked resistance to tetracycline and gentamycin. Based on our knowledge, this is the first report to identify MRSA ST1 in Egypt. Bovine mastitis could be a source for the dissemination of MRSA to humans and other animals. Additionally, while methicillin-resistance may have no effect on the clinical outcome of mastitis, it does affect therapeutic success, particularly when β-lactam antimicrobials are used.

855. Evolution of Group B Streptococcal Capsular Type V Invasive Infections in Neonates and Young Infants: A Whole Genome Sequencing Study

BackgroundSince 1970 group B Streptococcus (GBS) has been a frequent cause of sepsis or meningitis in young infants. Capsular polysaccharide type V was first recognized in 1990 and has increased to the point where it now causes ~15% of GBS infections. GBS type V strains are almost entirely sequence type 1 (ST1) in adult infections. To understand the emergence of type V GBS, we compared infant strains before 1990 to more contemporary isolates from young infants and adults.MethodsThirty-five strains isolated from blood or CSF of infants <90 days of age (Houston, 1979–1996) were compared with the following previously sequenced type V, ST1 strains: (1) 14 from infant blood or CSF from Center for Disease Control and Prevention (CDC) (2015–2017), (2) 193 blood ST1 isolates from adults (Houston, 1992–2013), and (3) 516 invasive isolates from the CDC (2015–2017). Isolates were sequenced using an Illumina MiSeq instrument followed by molecular typing, antimicrobial resistance gene determination, and phylogenetic analysis. Antimicrobial susceptibility testing (AST) was performed using disk diffusion and E-test.ResultsThe majority (29/35) of Houston young infant strains were ST1. Type V GBS strains isolated prior to 1990 were more likely to be of ST-2 or ST-26 (5/10) compared with those from 1990 or later (24/25 and 14/14 CDC infant invasive type V). Tetracycline resistance was identified in 83% (29/35) while macrolide resistance (MR) occurred in only 23% (8/35) of the strains. Compared with early neonatal isolates, MR was significantly more frequent among contemporary neonatal (12/14, 86%, P < 0.0001) and adult (502/710, 71%, P < 0.0001) ST1 GBS. Phylogenetic analysis showed two distinct clades defined, in part, by MR. A high-frequency MR (340/360, 94%) clade was defined by the presence of erm(B) on Tn3872 while the low-frequency MR clade (159/350, 45%) was more diverse in mobile elements contributing to MR. The majority (27/29) of early neonatal ST1 GBS strains were observed in the low-frequency MR clade.ConclusionInfant invasive disease due to type V GBS before 1990 consisted of more diverse STs but is now almost exclusively ST1. Differences in the frequency of MR between early neonatal and contemporary type V ST1 GBS suggest MR may, at least in part, have driven the expansion of type V ST1 GBS.Disclosures All Authors: No reported Disclosures.

626. Mobile Genetic Element Dynamics of Co-Circulating Klebsiella pneumoniae Sequence Types Carrying blaKPC in Houston, Texas

BackgroundCarbapenem-resistant Klebsiella pneumoniae (CR-Kpn) are a significant cause of hospital-associated infections. Class A β-lactamases, e.g., Klebsiella pneumoniae carbapenemases (KPCs), are major contributors to carbapenem resistance. Sequence type 258 (ST258) is the most common genetic lineage of CR-Kpn associated with blaKPC carriage. Recently, a newly emergent lineage ST307 has been identified within the Houston metropolitan region. The transmission of blaKPC and other antimicrobial resistance (AMR) genes is driven largely by exchange of mobile genetic elements (MGEs). We sought to describe the dynamics of horizontal gene transfer (HGT) in particular between co-circulating strains of ST307 and ST258.MethodsLong-read sequencing technologies allow us to resolve plasmid sequences and their associated AMR genes as well as characterize a comprehensive range of MGEs enabling transmission of these clinically important resistance mechanisms. CR-Kpn isolates were collected as part of a study to describe CRE burden within a Houston metropolitan hospital system. The Oxford Nanopore Technology (ONT) GridION X5 was used for long-read sequencing with Illumina short-read data used to refine and generate high-quality, consensus assemblies. A custom bioinformatic pipeline was used to resolve plasmid structures and identify the genomic context of plasmids carrying blaKPC variants.Results95 Kpn isolates were collected from May to December 2017. Phylogenetic and in silico MLST analysis revealed 38/95 (40%) and 35/95 (37%) were ST258 and ST307, respectively. 86% of Kpn isolates carried one or more IncF-type conjugative plasmids, which were the prime vectors for blaKPC intercellular transmission. Interestingly, we found similar AMR-harboring plasmids within ST258 and ST307 composed of mosaic, modular IS26 and Tn3-like transposase mediated elements that carried multiple AMR determinants including blaKPC variants (Figure 1).ConclusionWe were able to characterize mechanisms by which ST307 and ST258 lineages may transfer AMR determinants. There are clinically relevant implications to these HGT events that occur between these lineages as they may provide insights into how resistance differentially develops. Disclosures All authors: No reported disclosures.