Indistinguishable Isolates Research Articles

Investigation of the seasonal prevalence, phenotypic, and genotypic characteristics of Listeria monocytogenes in slaughterhouses in Burdur.

This study examined Listeria monocytogenes isolates from two slaughterhouses in Burdur province, southern Turkey, over four seasons for antibiotic resistance, serogroups, virulence genes, in vitro biofilm forming capacity, and genetic relatedness. Carcass (540) and environment-equipment surface (180) samples were collected from two slaughterhouses (S1, S2) for 1 year (4 samplings). Of the 89 (12.4%) positive isolates, 48 (53.9%) were from animal carcasses, and 41 (46.1%) from the environment-equipment surfaces. Autumn was the peak season for Listeria monocytogenes compared to summer and spring (P<0.05). In addition, the most common serotype between seasons was 1/2c. Except for plcA and luxS genes, all isolates (100%) harbored inlA, inlC, inlJ, hlyA, actA, iap, flaA genes. Listeria monocytogenes isolates were identified as belonging to IIc (1/2c-3c; 68.5%), IVb (4b-4d-4e; 29.2%), and IIa (1/2a-3a; 2.2%) in the screening using multiplex polymerase chain reaction-based serogrouping test. A total of 65 pulsotypes and 13 clusters with at least 80% homology were determined by using pulsed field gel electrophoresis on samples that had been digested with ApaI. Thirty-four (38.2%) of the isolates were not resistant to any of the 14 antibiotics tested. The antibiotic to which the isolates showed the most resistance was rifampicin (44.9%). Serotype 1/2c was the most resistant serotype to antibiotics. Despite having biofilm-associated genes (inlA, inlB, actA, flaA, and luxS), a minority (11%) of isolates formed weak biofilm. This study revealed seasonal changes prevalence of Listeria monocytogenes, particularly higher in autumn, posing a greater risk of meat contamination. Notably, Serotype 1/2c showed significant prevalence and antibiotic resistance. Indistinguishable isolates indicated cross-contamination, underscoring the importance of prioritized training for slaughterhouse personnel in sanitation and hygiene protocols.

1332. Population structure and genomic analysis of pediatric Streptococcus pyogenes clinical isolates in the United States, 2020 – 2022

Abstract Background Streptococcus pyogenes (GAS) is the major cause of bacterial pharyngitis in children. GAS can cause conditions ranging from asymptomatic pharyngeal carriage to invasive infection. We compared the genomic characteristics of GAS pharyngeal and invasive isolates from U.S. children. Methods We cultured GAS from throat swabs collected from children aged 3–18 years with acute GAS pharyngitis, diagnosed by rapid antigen or molecular test, and from a convenience sample of asymptomatic children during 1/2020 to 3/2022 in Chicago, IL; Atlanta, GA; Portland, OR; Phoenix, AZ. We collected invasive isolates in Chicago. Whole-genome sequencing (WGS) was performed on the Illumina MiSeq for species confirmation, isolate typing, and virulence and antimicrobial gene identification. Reference-based read alignment was used for whole genome phylogenetic analysis. Results Of 1144 collected throat swabs, 684 were from children with pharyngitis and 460 from asymptomatic children. 13 invasive GAS isolates were collected. GAS were cultured from 359 pharyngitis and 20 asymptomatic swabs. Of these, 371 GAS isolates could be recovered and underwent WGS. Thirty isolates (8%) were either low-quality sequences and/or identified as species other than S. pyogenes and were excluded. Whole-genome phylogenetic analysis of 341 GAS (215 pharyngitis, 13 asymptomatic, 13 invasive) identified 25 related clusters and 8 singletons (Figure 1). Virulence gene complements within given emm types were generally concordant with recently published CDC strain data. The most frequently identified resistance genes were tetM and ermB. 281 isolates (82%) carried no antibiotic resistance genes. Some clusters were significantly more represented at certain sites within apparent geographically defined clusters of nearly indistinguishable isolates (Figure 1): cluster 1 in Chicago, emm type 3; cluster 14 in Phoenix and Portland, emm 28, 12; and cluster 15 in Atlanta, emm 89. No major genomic factors were significantly associated with asymptomatic vs pharyngitis vs invasive presentation. Figure 1:Whole genome phylogenetic tree of pediatric GAS isolates Maximum likelihood phylogenetic analysis based on whole-genome alignment of 371 Group A Streptococcus isolates. Tip colors represent cluster assignments based on genetic similarity. Inner ring represents geographic location of GAS isolation. Outer ring represents patient presentation: asymptomatic colonization, symptomatic pharyngitis, or invasive infection. Conclusion Pharyngeal and invasive GAS in children within individual clonal complexes are co-included in closely related clusters, with evidence of close transmission within individual sites Disclosures All Authors: No reported disclosures.

Longitudinal observation of meticillin-resistant Staphylococcus pseudintermedius pulsotypes in six veterinary hospitals in the north-western United States.

BackgroundMeticillin‐resistant Staphylococcus pseudintermedius (MRSP) infections in companion animals are increasing and are difficult to treat. Environmental contamination with MRSP in small animal primary care hospitals may pose an exposure risk to animal patients.MethodsThis longitudinal study assessed the genotypic relationships of MRSP isolated from 39 environmental samples collected from six private small animal primary care hospitals, in the north‐eastern United States, between August 2018 and April 2019.ResultsOf the 39 bacterial isolates, 18 unique pulsotypes were identified based on pulsed‐field gel electrophoresis, including six clusters of two or more indistinguishable isolates. Single pulsotypes were frequently detected from multiple hand‐contact and animal‐contact surfaces within a hospital during a single sampling event, but detection of a single pulsotype within the same hospital on subsequent visits was infrequent. However, one pulsotype was recovered from three separate hospitals, which suggests that either MRSP transmission between hospitals may have occurred via people, animals, or fomites or that there was a dominant community strain.ConclusionsSingle strains of MRSP were isolated from various hand‐contact and animal‐contact surfaces within hospitals, indicating the important role of humans, animals and the environment in MRSP transmission. Additionally, the detection of a single strain between hospitals and over time suggests that either MRSP transmission between hospitals may have occurred via people, animals or fomites or that there was a dominant community strain.

Genetic Relationship of Salmonella Isolates Found in Subcutaneous Abscesses in Leopard Geckos (Eublepharis Macularius).

IntroductionThe article describes the occurrence and phylogenetic relationship of Salmonella isolates found in subcutaneous abscesses of leopard geckos. The aim of the study was to determine the cause of the abscesses and to characterise isolated Salmonella strains.Material and MethodsSamples of abscesses from five animals and internal organs (lungs, liver, and gut) of three of them were tested for Salmonella according to the PN-EN ISO 6579:2002/A1:2007 standard. The antimicrobial resistance was evaluated by minimal inhibitory concentrations and the genetic similarity of the isolates was assessed with pulsed field gel electrophoresis (PFGE).ResultsIn total, seventeen Salmonella isolates belonging to five different serovars were found to be susceptible to all tested antimicrobials except streptomycin. The serovars were S. Hadar, S. Fluntern, S. Tennessee, S. enterica subsp. salamae 55:k:z39, and S. Kentucky. Up to three serovars from different organs were isolated from the same individual. In two geckos, Salmonella were detected in the lungs. In three serovars, XbaI-PFGE typing revealed indistinguishable isolates from organs and abscesses.ConclusionMultiple Salmonella serovars might be involved in abscess formation and infections. The occurrence of the same PFGE profiles of the isolates may testify to the role of opportunistic organisms in causing infection.

Whole-genome sequencing to explore nosocomial transmission and virulence in neonatal methicillin-susceptible Staphylococcus aureus bacteremia

BackgroundNeonatal Staphylococcus aureus (S. aureus) bacteremia is an important cause of morbidity and mortality. In this study, we examined whether methicillin-susceptible S. aureus (MSSA) transmission and genetic makeup contribute to the occurrence of neonatal S. aureus bacteremia.MethodsA retrospective, single-centre study was performed. All patients were included who suffered from S. aureus bacteremia in the neonatal intensive care unit (NICU), Erasmus MC-Sophia, Rotterdam, the Netherlands, between January 2011 and November 2017. Whole-genome sequencing (WGS) was used to characterize the S. aureus isolates, as was also done in comparison to reference genomes. Transmission was considered likely in case of genetically indistinguishable S. aureus isolates.ResultsExcluding coagulase-negative staphylococci (CoNS), S. aureus was the most common cause of neonatal bacteremia. Twelve percent (n = 112) of all 926 positive blood cultures from neonates grew S. aureus. Based on core genome multilocus sequence typing (cgMLST), 12 clusters of genetically indistinguishable MSSA isolates were found, containing 33 isolates in total (2–4 isolates per cluster). In seven of these clusters, at least two of the identified MSSA isolates were collected within a time period of one month. Six virulence genes were present in 98–100% of all MSSA isolates. In comparison to S. aureus reference genomes, toxin genes encoding staphylococcal enterotoxin A (sea) and toxic shock syndrome toxin 1 (tsst-1) were present more often in the genomes of bacteremia isolates.ConclusionTransmission of MSSA is a contributing factor to the occurrence of S. aureus bacteremia in neonates. Sea and tsst-1 might play a role in neonatal S. aureus bacteremia.

Molecular Characteristics and Antimicrobial Susceptibility Profiles of Elizabethkingia Clinical Isolates in Shanghai, China.

PurposeTo investigate molecular characteristics and antimicrobial susceptibility profiles of clinical isolates of Elizabethkingia in Shanghai, China.MethodsElizabethkingia isolates were collected in a university-affiliated hospital in 2012–2015 and 2017–2018. They were re-identified to species level by 16S rRNA gene and species-specific gene sequencing. Antimicrobial susceptibility testing, screening for metallo-beta-lactamase production, identification of antimicrobial resistance genes and pulsed-field gel electrophoresis (PFGE) were performed.ResultsAmong 52 Elizabethkingia isolates, E. anophelis was the most prevalent species (67.3%), followed by E. meningoseptica (26.9%). High carriage rates of blaCME, blaBlaB and blaGOB genes were consistent with the poor in vitro activity of most β-lactams including carbapenems. Nevertheless, β-lactamase inhibitors increased susceptibility rates significantly for cefoperazone and piperacillin. Susceptibility rates for minocycline, tigecycline, rifampin and levofloxacin were 100%, 78.8%, 76.9% and 71.2%, respectively. Ser83Ile or Ser83Arg substitution in the DNA gyrase A unit was associated with resistance to fluoroquinolones. MIC50/MIC90 values of vancomycin and linezolid were 16/16 mg/L and 16/32 mg/L, respectively. Molecular typing showed twenty-one different types of PFGE and more than one indistinguishable isolates were observed in each of the eight subtypes.ConclusionTetracyclines, tigecycline, β-lactam/β-lactamase inhibitor combinations, rifampin and fluoroquinolones demonstrated high rates of in vitro activity against clinical isolates of Elizabethkingia. Both genetic diversity and clonality were observed from this health-care facility. Our report provides potential alternative treatment options for Elizabethkingia infections.

Neonatal Staphylococcus aureus acquisition at a tertiary intensive care unit

In this study, we explored the role of colonization in health care workers (HCWs) in transmission of methicillin-susceptible Staphylococcus aureus (MSSA) to neonates at a level IV neonatal intensive care unit (NICU). All available screening and clinical MSSA isolates, from the period March 2015 through April 2016, isolated from HCWs and neonates at the level IV NICU, were included. MSSA isolates were initially genotyped using spa typing, and for the most prevalent spa types, whole-genome sequencing (WGS) was performed. From March 2015 through April 2016, 159 neonates and 115 HCWs were found positive for MSSA, and all isolates were typed by means of spa typing. Twenty-three spa types were found in both HCWs and neonates. Within the most prevalent spa types (t002, t015 and t2787), 4 WGS clusters of genetically indistinguishable MSSA isolates were found in which 4 HCWs and 35 neonates were involved. A total of 10 neonates included in the 4 WGS clusters suffered from bacteremia. We showed that HCWs carried the same MSSA isolates as those found in neonates, and that HCWs might serve as a reservoir for transmission of MSSA to neonates. Ten neonates suffered from a bacteremia caused by a MSSA previously detected in a HCW.

Listeria monocytogenes isolates from ready to eat plant produce are diverse and have virulence potential

Listeria monocytogenes is sporadically detected on a range of ready to eat fresh produce lines, such as spinach and rocket, and is a threat to public health. However, little is known about the diversity of L. monocytogenes present on fresh produce and their potential pathogenicity. In this work, fifteen Listeria monocytogenes isolates from the UK fresh produce supply chain were characterised using whole genome sequencing (WGS). Additionally, isolates were characterised based on their ability to form biofilm. Whole genome sequencing data was used to determine the sequence type of isolates based on multi-locus sequence typing (MLST), construct a core single nucleotide polymorphism (SNP) phylogeny and determine the presence of virulence and resistance associated genes. MLST revealed 9 distinct sequence types (STs) spanning 2 lineages (I & II) with one isolate belonging to the ST6 subtype, strains from which have been recently implicated in two large, food-associated L. monocytogenes outbreaks in South Africa and across Europe. Although most of the 15 isolates were different, comparison of core genome SNPs showed 4 pairs of ‘indistinguishable’ strains (<5 SNPs difference). Virulence profiling revealed that some isolates completely lacked the Listeria pathogenicity island-3 (LIPI-3) amongst other virulence factors. Investigation of the inlA gene showed that no strains in this study contained a premature stop codon (PMSC), an indicator of attenuated virulence. Assessment of biofilm production showed that isolates found in the fresh produce supply chain differ in their ability to form biofilm. This trait is considered important for L. monocytogenes to persist in environments associated with food production and processing. Overall the work indicates that a genetically diverse range of L. monocytogenes strains is present in the UK fresh produce supply chain and the virulence profiles found suggests that at least some of the strains are capable of causing human illness. Interestingly, the presence of some genetically indistinguishable isolates within the 15 isolates examined suggests that cross-contamination in the fresh produce environment does occur. These findings have useful implications in terms of food safety and for informing microbial surveillance programmes in the UK fresh produce supply chain.

Healthcare-associated transmission of Panton-Valentine leucocidin positive methicillin-resistant Staphylococcus aureus: the value of screening asymptomatic healthcare workers

BackgroundThree patients hospitalised in the coronary care unit of a general district hospital (England, UK) were tested positive for Panton-Valentine leucocidin methicillin-resistant Staphylococcus aureus colonisation during their routine weekly screening for methicillin-resistant Staphylococcus aureus (MRSA). The isolates were indistinguishable and all three patients have previously had negative screening tests. The outbreak investigation team considered exploring the possibility of PVL-MRSA transmission from members of staff to the patients and potentially between members of staff.MethodAs part of the investigations, healthcare workers on coronary care unit and intensive care unit were screened for MRSA carriage.ResultsAmong 134 screened healthcare workers, five staff members (3.7%) were MRSA colonised. Among these isolates, four were Panton-Valentine leukocidin positive. However, only two healthcare workers had an indistinguishable isolate with the isolate identified among the colonised patients. Decolonisation treatment was offered to all colonised patients and healthcare workers.ConclusionIn low MRSA prevalence settings, healthcare workers may be a reservoir of MRSA and an important potential source of transmission to patients. Screening and decolonisation of colonised healthcare workers may provide a valuable strategy in managing linked hospital acquisitions and reduce the risk of occupationally acquired complications. MRSA mass screen of healthcare workers should be considered in transmission with a strain that has a potentially increased virulence, such as Panton-Valentine leucocidin methicillin-resistant Staphylococcus aureus.

Large outbreak of multiple gastrointestinal pathogens associated with fresh curry leaves in North East England, 2013.

A total of 592 people reported gastrointestinal illness following attendance at Street Spice, a food festival held in Newcastle-upon-Tyne, North East England in February/March 2013. Epidemiological, microbiological and environmental investigations were undertaken to identify the source and prevent further cases. Several epidemiological analyses were conducted; a cohort study; a follow-up survey of cases and capture re-capture to estimate the true burden of cases. Indistinguishable isolates of Salmonella Agona phage type 40 were identified in cases and on fresh curry leaves used in one of the accompaniments served at the event. Molecular testing indicated entero-aggregative Escherichia coli and Shigella also contributed to the burden of illness. Analytical studies found strong associations between illness and eating food from a particular stall and with food items including coconut chutney which contained fresh curry leaves. Further investigation of the food supply chain and food preparation techniques identified a lack of clear instruction on the use of fresh uncooked curry leaves in finished dishes and uncertainty about their status as a ready-to-eat product. We describe the investigation of one of the largest outbreaks of food poisoning in England, involving several gastrointestinal pathogens including a strain of Salmonella Agona not previously seen in the UK.

Transmission events revealed in tuberculosis contact investigations in London

Contact tracing is a key part of tuberculosis prevention and care, aiming to hasten diagnosis and prevent transmission. The proportion of case-contact pairs for which recent transmission occurred and the typical timespans between the index case and their contact accessing care are not known; we aimed to calculate these. We analysed individual-level TB contact tracing data, collected in London from 20/01/2011-31/12/2015, linked to tuberculosis surveillance and MIRU-VNTR 24-locus strain-typing information. Of pairs of index cases and contacts diagnosed with active tuberculosis, 85/314 (27%) had strain typing data available for both. Of these pairs, 79% (67/85) shared indistinguishable isolates, implying probable recent transmission. Of pairs in which both contact and the index case had a social risk factor, 11/11 (100%) shared indistinguishable isolates, compared to 55/75 (75%) of pairs in which neither had a social risk factor (P = 0.06). The median time interval between the index case and their contact accessing care was 42 days (IQR: 16, 96). As over 20% of pairs did probably not involve recent transmission between index case and contact, the effectiveness of contact tracing is not necessarily limited to those circumstances where the index case has transmitted disease to their close contacts.

The History of Bordetella pertussis Genome Evolution Includes Structural Rearrangement.

Despite high pertussis vaccine coverage, reported cases of whooping cough (pertussis) have increased over the last decade in the United States and other developed countries. Although Bordetella pertussis is well known for its limited gene sequence variation, recent advances in long-read sequencing technology have begun to reveal genomic structural heterogeneity among otherwise indistinguishable isolates, even within geographically or temporally defined epidemics. We have compared rearrangements among complete genome assemblies from 257 B. pertussis isolates to examine the potential evolution of the chromosomal structure in a pathogen with minimal gene nucleotide sequence diversity. Discrete changes in gene order were identified that differentiated genomes from vaccine reference strains and clinical isolates of various genotypes, frequently along phylogenetic boundaries defined by single nucleotide polymorphisms. The observed rearrangements were primarily large inversions centered on the replication origin or terminus and flanked by IS481, a mobile genetic element with >240 copies per genome and previously suspected to mediate rearrangements and deletions by homologous recombination. These data illustrate that structural genome evolution in B. pertussis is not limited to reduction but also includes rearrangement. Therefore, although genomes of clinical isolates are structurally diverse, specific changes in gene order are conserved, perhaps due to positive selection, providing novel information for investigating disease resurgence and molecular epidemiology.IMPORTANCE Whooping cough, primarily caused by Bordetella pertussis, has resurged in the United States even though the coverage with pertussis-containing vaccines remains high. The rise in reported cases has included increased disease rates among all vaccinated age groups, provoking questions about the pathogen's evolution. The chromosome of B. pertussis includes a large number of repetitive mobile genetic elements that obstruct genome analysis. However, these mobile elements facilitate large rearrangements that alter the order and orientation of essential protein-encoding genes, which otherwise exhibit little nucleotide sequence diversity. By comparing the complete genome assemblies from 257 isolates, we show that specific rearrangements have been conserved throughout recent evolutionary history, perhaps by eliciting changes in gene expression, which may also provide useful information for molecular epidemiology.

First report on whole-genome shotgun sequences of 23 biochemically indistinguishable clinical Shigella isolates.

Shigella spp. are a major diarrhoeal disease pathogen worldwide and can cause considerable morbidity and mortality. Notably, limited genome data are available for serogroups/sub-serogroups of Shigella. Here we report the whole-genome shotgun sequences of 23 non-typeable Shigella from stool specimens that biochemically resembled Shigella spp. but were non-typeable with Shigella-specific antisera.

Carbapenemase-producing Enterobacteriaceae in hospital wastewater: a reservoir that may be unrelated to clinical isolates

Carbapenemase-producing Enterobacteriaceae (CPE) are an emerging infection control problem in hospitals worldwide. Identifying carriers may help reduce potential spread and infections. To assess whether testing hospital wastewater for CPE can supplement patient-based screening for infection prevention purposes in a hospital without a recognized endemic CPE problem. Wastewater collected from hospital pipework on 16 occasions during February to March 2014 was screened for CPE using chromID(®) CARBA agar and chromID(®) CPS agar with a 10μg ertapenem disc and combination disc testing. Minimum inhibitory concentrations were determined using British Society for Antimicrobial Chemotherapy methodology and carbapenemase genes detected by polymerase chain reaction or whole-genome sequencing. Selected isolates were typed by pulsed-field gel electrophoresis. Suspected CPE were recovered from all 16 wastewater samples. Of 17 isolates sent to the Antimicrobial Resistance and Healthcare Associated Infections Reference Unit, six (four Citrobacter freundii and two Enterobacter cloacae complex) were New Delhi metallo-β-lactamase (NDM) producers and the remaining 11 (six Klebsiella oxytoca and five Enterobacter cloacae complex) were Guiana-Extended-Spectrum-5 (GES-5) producers, the first to be described among Enterobacteriaceae in the UK. The four NDM-producing C.freundii, two NDM-producing E.cloacae complex, and four out of five GES-5-producing E.cloacae complex were each indistinguishable isolates of the same three strains, whereas the six GES-5-producing K.oxytoca overall shared 79% similarity. CPE are readily isolated from hospital wastewater using simple culture methods. There are either undetected carriers of CPE excreting into the wastewater, or these CPE represent colonization of the pipework from other sources. Surveillance of hospital wastewater for CPE does not appear helpful for infection control purposes within acute hospitals.

Whole-Genome Sequencing Allows for Improved Identification of Persistent Listeria monocytogenes in Food-Associated Environments.

While the food-borne pathogen Listeria monocytogenes can persist in food associated environments, there are no whole-genome sequence (WGS) based methods to differentiate persistent from sporadic strains. Whole-genome sequencing of 188 isolates from a longitudinal study of L. monocytogenes in retail delis was used to (i) apply single-nucleotide polymorphism (SNP)-based phylogenetics for subtyping of L. monocytogenes, (ii) use SNP counts to differentiate persistent from repeatedly reintroduced strains, and (iii) identify genetic determinants of L. monocytogenes persistence. WGS analysis revealed three prophage regions that explained differences between three pairs of phylogenetically similar populations with pulsed-field gel electrophoresis types that differed by ≤3 bands. WGS-SNP-based phylogenetics found that putatively persistent L. monocytogenes represent SNP patterns (i) unique to a single retail deli, supporting persistence within the deli (11 clades), (ii) unique to a single state, supporting clonal spread within a state (7 clades), or (iii) spanning multiple states (5 clades). Isolates that formed one of 11 deli-specific clades differed by a median of 10 SNPs or fewer. Isolates from 12 putative persistence events had significantly fewer SNPs (median, 2 to 22 SNPs) than between isolates of the same subtype from other delis (median up to 77 SNPs), supporting persistence of the strain. In 13 events, nearly indistinguishable isolates (0 to 1 SNP) were found across multiple delis. No individual genes were enriched among persistent isolates compared to sporadic isolates. Our data show that WGS analysis improves food-borne pathogen subtyping and identification of persistent bacterial pathogens in food associated environments.

Whole-genome sequencing in hierarchy with pulsed-field gel electrophoresis: the utility of this approach to establish possible sources of MRSA cross-transmission

In order to study the micro-epidemiology of meticillin-resistant Staphylococcus aureus (MRSA) effectively, the molecular typing method used must be able to distinguish between different MRSA strains. Pulsed-field gel electrophoresis (PFGE) can detect small genetic differences but is limited in its potential to distinguish isolates within a major lineage. Whole-genome sequencing (WGS) provides sufficient resolution to support or exclude links between otherwise indistinguishable isolates, but lacks the practical utility of conventional typing methods. To explore the utility of WGS in a hierarchical approach with PFGE to help establish possible sources of MRSA cross-transmission in the intensive care setting. Possible transmission routes from donor to recipient via the hands of staff, the air or environmental surfaces were identified. Focused molecular typing used PFGE to explore these transmission hypotheses. WGS was applied when an acquisition event involved a common PFGE pulsotype. Thirty-eight of the 78 acquisition events could not be explored as clinical isolates were not available. PFGE excluded all potential donors from 26 of the remaining 40 acquisition events, but did identify a probable source in 14 new colonizations. Within the hypotheses tested, PFGE supported links between patients occupying the same bay, the same bed space, adjacent isolation rooms and different wards. When a patient source was not identified, PFGE implicated the ward environment and the hands of staff. However, WGS disproved three of these transmission pathways. WGS can complement conventional typing methods by confirming or refuting possible MRSA transmission hypotheses. Epidemiological data are crucial in this process.

Clonal evolution multi-drug resistant Acinetobacter baumannii by pulsed-field gel electrophoresis.

Acinetobacter baumannii is usually multi-drug resistant (MDR), including third generation cephalosporins, amino glycosides and fluoroquinolone. Resistance to these antibiotics is mediated by multiple factors such as: lactamases, efflux pumps and other mechanisms of resistance. Pulsed-field gel electrophoresis (PFGE) was then used to investigate the genetic relationships among the MDR isolates. The aim of this study was to determine MDR isolates and the existence of OXAs genes among MDR isolates of A. baumannii collected from Kermanshah hospitals in west of Iran. Forty-two MDR A. baumannii were collected from patients at Kermanshah hospitals. The isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics by disk diffusion method was determined. Polymerase chain reaction (PCR) was performed for detection of blaOXA-23-like , blaOXA-24-like , blaOXA-51-like and blaOXA-58-like betalactamase genes in isolates and clonal relatedness was done by PFGE (with the restriction enzyme ApaI) and patterns analyzed by Bionumeric software. This study showed high resistant to ciprofloxacin, piperacillin, ceftazidime and also resistant to other anti-microbial agents and more spread blaOXA-23-like gene (93%) in MDR isolate. The PFGE method obtained six clones: A (10), B (9), C (5), D (4), E (11) and F (3) that clone E was outbreak and dominant in different wards of hospitals studied. An isolate from the emergency ward of these hospitals had indistinguishable isolates PFGE profile and similar resistance profile to isolates from intensive care unit (ICU), suggesting likely transmission from ICU to emergency via patient or hospital staff contact.

Formal Revision of the Alexandrium tamarense Species Complex (Dinophyceae) Taxonomy: The Introduction of Five Species with Emphasis on Molecular-based (rDNA) Classification

The Alexandrium tamarense species complex is one of the most studied marine dinoflagellate groups due to its ecological, toxicological and economic importance. Several members of this complex produce saxitoxin and its congeners - potent neurotoxins that cause paralytic shellfish poisoning. Isolates from this complex are assigned to A. tamarense, A. fundyense, or A. catenella based on two main morphological characters: the ability to form chains and the presence/absence of a ventral pore between Plates 1' and 4'. However, studies have shown that these characters are not consistent and/or distinctive. Further, phylogenies based on multiple regions in the rDNA operon indicate that the sequences from morphologically indistinguishable isolates partition into five clades. These clades were initially named based on their presumed geographic distribution, but recently were renamed as Groups I-V following the discovery of sympatry among some groups. In this study we present data on morphology, ITS/5.8S genetic distances, ITS2 compensatory base changes, mating incompatibilities, toxicity, the sxtA toxin synthesis gene, and rDNA phylogenies. All results were consistent with each group representing a distinct cryptic species. Accordingly, the groups were assigned species names as follows: Group I, A. fundyense; Group II, A. mediterraneum; Group III, A. tamarense; Group IV, A. pacificum; Group V, A. australiense.

(2302) Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae).

TAXONVolume 63, Issue 4 p. 932-933 Proposals to Conserve or Reject NamesFree Access (2302) Proposal to reject the name Gonyaulax catenella (Alexandrium catenella) (Dinophyceae) Uwe John, Corresponding Author Uwe John uwe.john@awi.de Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 GermanySearch for more papers by this authorWayne Litaker, Wayne Litaker National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Oceans Science, Center for Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, North Carolina, 28516 U.S.A.Search for more papers by this authorMarina Montresor, Marina Montresor Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, 80121 ItalySearch for more papers by this authorShauna Murray, Shauna Murray Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, P.O. Box 123 Broadway, New South Wales, 2007 AustraliaSearch for more papers by this authorMichael L. Brosnahan, Michael L. Brosnahan Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543 U.S.A.Search for more papers by this authorDonald M. Anderson, Donald M. Anderson Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543 U.S.A.Search for more papers by this author Uwe John, Corresponding Author Uwe John uwe.john@awi.de Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570 GermanySearch for more papers by this authorWayne Litaker, Wayne Litaker National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Oceans Science, Center for Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, North Carolina, 28516 U.S.A.Search for more papers by this authorMarina Montresor, Marina Montresor Stazione Zoologica Anton Dohrn, Villa Comunale, Napoli, 80121 ItalySearch for more papers by this authorShauna Murray, Shauna Murray Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, P.O. Box 123 Broadway, New South Wales, 2007 AustraliaSearch for more papers by this authorMichael L. Brosnahan, Michael L. Brosnahan Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543 U.S.A.Search for more papers by this authorDonald M. Anderson, Donald M. Anderson Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts, 02543 U.S.A.Search for more papers by this author First published: 01 August 2014 https://doi.org/10.12705/634.21Citations: 25AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume63, Issue4August 2014Pages 932-933 RelatedInformation

Carriage of Staphylococcus aureus in Thika Level 5 Hospital, Kenya: a cross-sectional study.

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial pathogen but little is known about its circulation in hospitals in developing countries. We aimed to describe carriage of S.aureus amongst inpatients in a mid-sized Kenyan government hospital.MethodsWe determined the frequency of S.aureus and MRSA carriage amongst inpatients in Thika Hospital, Kenya by means of repeated cross-sectional ward surveys. For all S.aureus isolates, we performed antibiotic susceptibility tests, genomic profiling using a DNA microarray and spa typing and MLST.ResultsIn this typical mid-sized Kenyan Government hospital, we performed 950 screens for current carriage of S.aureus amongst inpatients over a four month period. We detected S.aureus carriage (either MSSA or MRSA) in 8.9% (85/950; 95%CI 7.1-10.8) of inpatient screens, but patients with multiple screens were more likely have detection of carriage. MRSA carriage was rare amongst S.aureus strains carried by hospital inpatients – only 7.0% (6/86; 95%CI 1.5-12.5%) of all isolates were MRSA. Most MRSA (5/6) were obtained from burns patients with prolonged admissions, who only represented a small proportion of the inpatient population. All MRSA strains were of the same clone (MLST ST239; spa type t037) with concurrent resistance to multiple antibiotic classes. MSSA isolates were diverse and rarely expressed antibiotic resistance except against benzyl-penicillin and co-trimoxazole.ConclusionsAlthough carriage rates for S.aureus and the MRSA prevalence in this Kenyan hospital were both low, burns patient were identified as a high risk group for carriage. The high frequency of genetically indistinguishable isolates suggests that there was local transmission of both MRSA and MSSA.