The lack of gyrA mutations in some isolates together with the pre

The lack of gyrA mutations in some isolates together with the presence of parC mutations in six other isolates is a unique finding. Although the Thr57Ser substitution in ParC has been reported previously

in Salmonella, it is detected less frequently compared with the more common gyrA mutations and typically occurs concomitantly with double gyrA mutations (Piddock et Obeticholic Acid supplier al. 1998; Baucheron et al., 2005; Hopkins et al., 2005). The Thr57Ser mutation in parC was first reported by Ling et al. (2003) in Salmonella isolates with a wild-type DNA gyrase and others possessing single gyrA mutations, wherein the first were susceptible to ciprofloxacin (MIC=0.06 μg mL−1), and the latter demonstrated a twofold increased resistance. More recently, Baucheron et al. (2005) reported that the Thr57Ser ParC substitution was not involved in quinolone resistance in their isolates. Also, Cui et al. (2009) reported an identical ParC substitution in a ciprofloxacin-resistant S. Rissen isolate that did not carry any other target gene mutation, qnr alleles nor an aac-(6′)-Ib-cr gene. In addition, the same polymorphism

was recently encountered in a number of non-Typhimurium isolates and the resistant phenotype could not be linked with this alteration because susceptible isolates harboured identical mutations (Gunell et al., 2009). Thus, we also sequenced the parC gene of Ipilimumab 10 randomly selected quinolone-susceptible isolates from this collection representing five serotypes. Thr57Ser substitution was identified in nine of 10 of these isolates (data not shown), Carbohydrate supporting the view that this is a common polymorphism in serotypes other than Typhimurium. In view of current knowledge regarding quinolone resistance mechanisms, it is unclear whether secondary target mutations alone can lead to the development of high-level quinolone resistance (Ling et al., 2003; Baucheron et al., 2005; Cui et al., 2009; Gunell et al., 2009). PCR analysis of the fluoroquinolone-resistant isolates did not detect aac(6′)-Ib-cr, qepA, qnrA nor qnrS genes. Four isolates were positive for qnrB (Table 4): one Infantis (S20), two Uganda isolates (S24, S38) and one

serovar 6,7:d:- isolate (S75). The MICs of nalidixic acid in these isolates varied from 32 to 256 μg mL−1. DNA sequencing revealed the presence of the qnrB19 allele in all cases. Multiple plasmids were present in nine isolates (data not shown) while four other isolates (denoted as S37, S45, S47 and S51) lacked detectable plasmids. In the plasmid-positive qnrB19 isolates S20, S24, S38 and S75, several other low-molecular-weight plasmids ranging in size between 1 and 3 kb were also noted (data not shown). When analysed by PCR designed to amplify ColE-like plasmids, amplicons of 2.7 kb were recovered. Among these, two distinct MboII RFLP profiles were observed, which were identical for three isolates (S20, S24, and S38), and different for isolate S75 (data not shown).

The gene encoding PGN_1476 in the PorSS-deficient strain was expr

The gene encoding PGN_1476 in the PorSS-deficient strain was expressed about three times more than that in the PorSS- proficient strain. As the relative amounts of the protein spots were < 20% (Table 2), the results suggest that decrease of the 10 secreted proteins in the PorSS-deficient mutant are

mostly dependent on the defect in the PorSS. The 10 PorSS-dependently secreted proteins as well as precursor Tacrolimus mw forms of Arg-gingipains (RgpA and RgpB) and Lys-gingipain (Kgp) had CTDs in which the conserved DxxG and GxY motifs and the conserved Lys residue are located (Seers et al., 2006; Fig. 5). Seers et al. (2006) reported that 34 CTD family proteins with sequence similarity to the C-terminal region of the RgpB precursor

were identified by a blast search with the P. gingivalis W83 genome, which include the 10 proteins identified in the present Obeticholic Acid in vitro study. Slakeski et al. (2010) suggested that the CTD of RgpB is essential for covalent attachment to the cell surface by an A-LPS anchor containing anionic polysaccharide repeating units. In our previous studies (Kondo et al., 2010; Shoji et al., 2011), we demonstrated that HBP35 and TapA were modified by A-LPS and anchored on the bacterial cell surface. In addition, the green fluorescent protein–CTD fusion study revealed that the CTDs of CPG70, PAD and HBP35 as well as RgpB play roles in PorSS-dependent translocation and glycosylation (Shoji et al., 2011). We suggested in the study both that the CTD region functions as a recognition signal for the PorSS and that glycosylation of CTD proteins occurs after removal of the CTD region. Cleaved CTD fragments of HBP35, CPG70, PAD, RgpB and PGN_1767 have recently been found in the culture supernatants of P. gingivalis (Glew et al., 2012), which is consistent with the present study and supports

our model (Shoji et al., 2011). Our results strongly indicate that the P. gingivalis secreted proteins with CTDs, which are responsible for colony pigmentation, hemagglutination, adherence and modification/processing of the bacterial surface proteins and host Olopatadine proteins, are translocated to the cell surface by the PorSS. In the present study, using 2D-PAGE and MS we identified 10 proteins secreted into the extracellular milieu by the PorSS. All of the proteins possessed CTDs. They included HBP35 in heme acquisition, TapA in virulence, PAD in citrullination of C-terminal Arg residues of the surface proteins and CPG70 in processing of C-terminal Arg and Lys residues. These results indicate that the PorSS is used for secretion of a number of proteins other than gingipains and that the CTDs of the proteins are associated with the PorSS-dependent secretion.

Participants reported that the adult consultants did not really k

Participants reported that the adult consultants did not really know them or understand their diabetes. at

the children’s clinic I had thorough appointments and saw doctor, nurse and dietitian. More recently, my appointments are a complete waste of time, seeing a different doctor every time for AZD1208 mouse a maximum of 5 minutes … I can’t remember the last time I saw a nurse or dietitian,’ (Young Person [YP], 22). Children, young people and parents had little knowledge of a care plan or any idea what was meant by a care plan. Very few participants had been given information following diagnosis about what would happen next, either in the short- or long-term. Few participants had been told about complications, especially long-term complications, nor were they always involved in discussions relating to alternative treatments, e.g. pump therapy. Most participants who accessed paediatric diabetes services

felt that they had learnt the majority of what they Seliciclib mw knew about their condition from others with T1DM. They stated that they would welcome the opportunity to attend a structured education workshop similar to the DAFNE course13 offered as part of adult services. Children and young people who had attended structured education sessions were in the minority, but commented on how helpful they were. I was invited to a carb-counting class to help me understand how to read labels and be confident with carb-counting. This class was really helpful,’ (YP, 17). A lack of awareness of T1DM among the public and GPs was highlighted as a major concern among participants. It was noted that most members of the public seemed to be unaware of the difference between T1DM and type 2 diabetes mellitus, and GPs were slow to detect the symptoms of diabetes, which led to a delay in diagnosis. I went to the doctor on three occasions and was told each time nothing was

wrong. On the third occasion I was told I would be reported to social services for being an over-protective parent!’ next (Parent of 16 year old). In addition, participants thought that ward staff needed more education on T1DM as they were often unaware of how to treat the condition. In general, there was a lack of education provided by diabetes staff in relation to healthy lifestyles, sexual health and pregnancy. Many parents and young adults conducted their own research on the internet, in order to find out what they needed to know. Those participants who accessed paediatric diabetes services reported having a good relationship with their diabetes team. In general, parents felt that communication was not a problem, since they were able to contact their diabetes specialist nurse at any time about their child. However, those children and young people who had a greater understanding of their diabetes wanted to have more input into their care, be involved in decision-making and be given more responsibility.

H67 and H349 act as active site Zn2+ ligands in the H influenzae

H67 and H349 act as active site Zn2+ ligands in the H. influenzae DapE (Gillner et al., 2009b), with E134 shown to function as both a general acid and a general base during catalysis (Bzymek & Holz, 2004). DapE is activated by several divalent metal ions, including Zn2+, Co2+, Cd2+ and Mn2+ (Born et al., 1998; Bienvenue et al., 2003). In the presence of Mn2+, Salmonella typhi DapE functions as an aspartyl dipeptidase (Broder & Miller, 2003). DapE proteins are known to bind two divalent cations: one with high affinity (Zn2+) and the other with lower affinity (Mn2+) (Broder & Miller, 2003). DapEs exhibit a strict specificity for the l,l-isoform of SDAP (Bienvenue et al., 2003; Nocek et al., 2010). Recently, the

crystal structures of H. influenzae selleck DapE Selleck AZD9291 with one or two zinc ions bound in the active site have been solved to 2 and 2.3 Ǻ resolution, respectively (Nocek et al., 2010). Previous to this, the 1.9 Å structure

of the apo form of DapE from N. meningitidis containing no metal ions was reported (Badger et al., 2005; Gillner et al., 2009b). Neisseria meningitidis DapE has a catalytic domain (residues 1–179 and 295–381) interrupted by a dimerization domain (180–294), and residues His68, Asp101, Glu136, Glu164 and His350 are involved in binding the two zinc atoms (Badger et al., 2005). Zn K-edge-extended X-ray absorption fine structure (EXAFS) spectra of H. influenzae DapE enzyme provided structural information on the active site and also helped establish the binding modes of phosphonate- and thiolate-containing inhibitors (Cosper et al., 2003). Two known competitive inhibitors of DapE are 2-carboxyethylphosphonic acid (CEPA) and 5-mercaptopentanoic acid (MSPA). The thiol group of MSPA binds to one or more of the Zn2+ ions in the active site of H. influenzae DapE (Cosper et al., 2003). Additionally, both l,l- and d,l-diaminopimelic acids are competitive inhibitors with respect to substrate (Born et al., 1998). A number of micromolar inhibitors of H. influenzae DapE were obtained by screening

compounds containing zinc-binding groups which included thiols, carboxylic acids, boronic acids, phosphonates and hydroxamates (Gillner et al., 2009a). The dapE deletion mutants generated in H. pylori and M. smegmatis were lethal and confirmed that dapE is essential for bacterial Thiamine-diphosphate kinase cell growth and proliferation (Pavelka & Jacobs, 1996; Karita et al., 1997; Davis et al., 2006). The H. pylori dapE deletion mutant was unable to grow in spite of the addition of lysine to the growth medium (Karita et al., 1997; Gillner et al., 2009b). The racemization of amino acids provides meso-DAP which gets incorporated into bacterial PG (Koo & Blanchard, 1999) (Fig. 3). DAP epimerase (DapF) is a unique member of the family of pyridoxal phosphate–independent amino acid racemases, and its substrates (ll-DAP and meso-DAP) contain two stereocentres (Pillai et al., 2006).

This indicates that prudent use of antimicrobials for swine disea

This indicates that prudent use of antimicrobials for swine disease prevention may contribute to reducing coselection of resistant pathogens with increasing VGs. Fortunately, E. coli strains resistant to kanamycin and doxycycline, which are used both in humans and in animals, were associated with a significantly reduced prevalence of certain virulence traits, resulting in a slightly reduced inferred virulence potential compared with susceptible isolates. The findings Bleomycin cost indicate that the correlations between AMR and VGs may vary according to different resistance phenotypes. Previous studies

have reported that the prevalence selleckchem of VGs in resistant isolates from animals did not differ compared

with susceptible counterparts (Johnson et al., 2003; Rosengren et al., 2009). The apparent contradiction may depend on the particular antimicrobial agents, VGs, and the geographical origin of the strains under investigation. A biological basis for the relationship of AMR with VGs in E. coli has been reported previously for certain genes; for example, the pCG86 plasmid comprising sulfadiazine, streptomycin, and tetracycline resistance genes has been associated with LT ST expression in swine strains (Gyles et al., 1977), and another plasmid coding for ampicillin resistance has been associated with genes for ST synthesis (including the STa and STb genes) from human strains (Stieglitz et al., 1980). The recent emergence of a new porcine ETEC strain with a new plasmid pTENT2 conferring combined virulence and AMR may also support these associations pentoxifylline (Leclerc et al., 2007). In our laboratory, we are currently investigating whether gene linkage on plasmids or other mobile genetic elements underlies the associations observed in this study. In conclusion, our findings show that AMR and VGs are quite prevalent in E. coli strains from diseased swine, and that there is a clear association between resistance

phenotypes and VGs. The increase in AMR and the emergence of relationships between AMR and VGs suggest that there is a great need for surveillance programs to monitor AMR in pathogenic bacteria that can be potentially transmitted to humans from food animals. Such surveillance programs would provide reasonable guidance for the use of antimicrobials in food animal production and would be an important step in our efforts to understand and control the emergence and spread of resistance and VGs. We thank Dr Mark Webber for critically reviewing the manuscript. We thank Professor Song Gao (College of Veterinary Medicine, Yangzhou University) for providing the control strains.

The CCC (CTN222) is a prospective multicentre study recruiting co

The CCC (CTN222) is a prospective multicentre study recruiting coinfected patients from existing

HIV clinic populations at 16 centres across five Canadian provinces (Fig. 1). The cohort was initiated in 2003 in Montreal, Quebec, and then was expanded to other urban and semi-urban centres in 2007. As of October 2010, 955 patients were enrolled. Details on the cohort PD-1 antibody design and protocol are reported elsewhere [9]. Eligible patients were adults aged over 16 years with documented HIV infection [enzyme-linked immunosorbent assay (ELISA) with western blot confirmation] and with chronic HCV infection or evidence of HCV exposure (e.g. HCV-seropositive by ELISA with recombinant immunoblot assay version II (RIBA II) or encoded antigen/enzyme immuno assay (EIA) confirmation, Doxorubicin purchase and/or HCV RNA positive). All potentially eligible patients were invited to participate to avoid selection bias. Patients who initially refused were eligible to enrol in future. The study was approved by the community advisory committee of the Canadian Institutes of Health Research (CIHR)-Canadian HIV Trials Network and by all institutional ethics boards of participating centres. Patients received $15 per visit to compensate for out-of-pocket expenses. After providing informed consent, each participant underwent an initial evaluation followed by study visits approximately every 6 months. Sociodemographic, behavioural, medical and treatment data

were collected using a standardized questionnaire in either English or French. Questionnaires were self-completed or completed with the assistance of a research assistant/nurse. Standard instruments were used to measure quality of life (EQ-5D™) [10]. Additionally, charts were abstracted by research personnel to obtain historical data such as nadir CD4 T-cell count, HIV RNA and all prior HIV and HCV treatment histories and diagnoses. Treatment and diagnostic data were updated

by research personnel at each follow-up visit. At baseline and each subsequent visit, laboratory assessments were performed, including complete blood count, serum chemistry, liver profile, Inositol monophosphatase 1 plasma HIV RNA, absolute and relative CD4 lymphocyte counts and plasma HCV RNA. The duration of HCV infection was determined using the date of HCV seroconversion, if known, or the year of first injecting drug use (IDU) or blood product exposure as a proxy of HCV infection [11]. ART was defined as taking at least three antiretrovirals concurrently. AIDS diagnoses were defined according to the Centers for Disease Control and Prevention classification (e.g. not by CD4 cell criteria alone) [12]. The aspartate aminotransferase (AST) to platelet ratio index (APRI) was used as a noninvasive surrogate for liver fibrosis and defined as: 100 × (AST/upper limit of normal)/platelet count (109/L) [13, 14]. An APRI score > 1.5 was considered to indicate significant fibrosis (corresponding to a biopsy score > F2) [14].

The translocation of T3SS effectors into host

The translocation of T3SS effectors into host 3-Methyladenine solubility dmso cells is the most distinctive function of T3SSs. However, the secretion of T3SS effectors is thought to be a different event from translocation (Lee & Galan, 2004) because there are several examples of exceptions in which constructs of the amino-terminal signal sequence of T3SS effectors fused

with a reporter protein can be observed in the supernatant and not inside host cells (Lee & Galan, 2004). To exclude this possibility for VocC, a translocation assay using VopC fused with the catalytic domain of CyaA was performed (Sory et al., 1995). This assay determines whether a T3SS effector–CyaA fusion is injected into eukaryotic cells by measuring intracellular cAMP levels because the activity of the CyaA catalytic domain requires calmodulin within eukaryotic cells. The wild-type strain expressing the VopC–CyaA fusion induced a high level of cAMP inside Caco-2 cells, while the ∆vocC strain did not, producing levels similar to the negative control (the T3SS2-deficient strain, vcrD2) (Fig. 3).

These results indicate that VocC is necessary for not only the secretion of VopC but also its translocation into host cells. Another characteristic of T3SS chaperones is the ability to bind their cognate effector. As expected from the screening assay used to identify T3SS2-associated chaperones (Fig. 1), VocC appeared to bind VopC. In this binding experiment, purified proteins were used to observe direct binding between the chaperone and an effector. A pull-down assay was performed using purified GST–VocC (42.6 kDa) and poly-histidine-tagged VopC (VopC–HIS; 45.9 kDa). Crizotinib research buy As shown in Fig. 4, GST–VocC coprecipitated Nutlin-3 chemical structure with VopC–HIS, while GST alone as a negative control did not. Another presumable substrate

for VocC, VopT, fused with a poly-histidine tag showed similar binding results to GST–VocC (data not shown). In previous studies, the binding of T3SS-associated chaperones and effectors and the amino-terminal secretion signal of effectors were required for efficient secretion via the T3SS (Arnold et al., 2009). Therefore, it was important to identify the chaperone-binding domain and the amino-terminal secretion signal of VopC. First, we used a series of truncated VopC mutants fused with CyaA in a pull-down assay with GST–VocC. As shown in Fig. 5a, the domain covering at least 100 amino acids from the amino terminus of VopC was responsible for binding to VocC. Additional pull-down assays using VopC21–100–CyaA showed that VocC bound to the amino-terminal 21–100 amino acids of VopC (Fig. 5b). Next, we examined whether an amino-terminal secretion signal existed in VopC. A secretion assay using V. parahaemolyticus T3SS1-deficient strains (ΔvcrD1) expressing a series of truncated VopC mutants fused with CyaA was carried out to assess the specific secretion of VopC fusions through T3SS2 (Fig. 5c).

We recommend the establishment of an efficient local prescribing

We recommend the establishment of an efficient local prescribing policy through an effective practice-based Pharmacy and Therapeutic Committee, training in prescribing to be introduced

in medical schools and the lending of support to continuous education programmes targeting prescribing skills. “
“Objective  Large numbers of drugs are prescribed antenatally, many of which are off-label or unlicensed. An off-label medication is one which does have a market authorisation, but for a different indication, dose, route or patient group than that for which it is prescribed. The purpose of this study was to determine how commonly these prescriptions are written at Liverpool Women’s GSK2118436 chemical structure Hospital (LWH), a unit with 8000 deliveries per annum. Methods  All inpatient prescriptions received from antenatal areas at LWH during a 3-month period were analysed. The drugs were divided into categories according to their licence, FDA class

and degree of clinical risk. Key findings  Some 17 694 prescriptions of 235 different drugs were prescribed during this period. Thirty-seven (16%) drugs and 4445 (25%) medications prescribed were licensed for use in pregnancy; 57 (24%) drugs and 3363 (19%) of the total prescriptions were off-label but considered safe by the manufacturers (e.g. erythromycin, prochlorperazine and clotrimazole); 138 (58%) drugs and 9722 (55%) prescriptions were cautioned or contraindicated by the manufacturer in pregnancy (e.g. cefalexin, magnesium sulphate and nifedipine). After further investigation into the safety of the off-label medications from the FDA safety profile and with the opinion of a multidisciplinary team, we were able to draw up a list of high-risk off-label medicines. This consisted of 38 drugs (16% of total) and 1735 (10%) of the total prescriptions (e.g. lisinopril, diazepam and morphine). Conclusions  A significant number of prescriptions

being used in an off-label manner at CHIR-99021 cell line LWH are high risk. Prescribers need to be aware of the risks associated with these drugs and the possible legal consequences of prescribing and administering them. “
“Objective  Thrombolysis decreases the chance of post-stroke dependence, although its use carries significant risk, notably of intra-cerebral haemorrhage. Patients (and families) face an important risk/benefit decision before consenting. We drafted a patient information booklet for this purpose, and applied performance-based readability testing with the aim that the most important information in the booklet could be found and understood. Methods  The booklet was developed with reference to best practice in information writing and design. We User-Tested its performance on 56 people without prior experience of stroke. After reading the booklet they were asked to find and explain 15 pieces of information.

, 2008) Translocation of CagA and by which induced IL-8 producti

, 2008). Translocation of CagA and by which induced IL-8 production in infected AGS cells is also blocked by cholesterol depletion (Lai et al., 2008; Murata-Kamiya et al., 2010). The presence of a single Glu-Pro-Ile-Tyr-Ala (EPIYA) motif in the C-terminal region of CagA was shown to be crucial for membrane localization (Higashi et al., 2005). Delivery of CagA with more phosphorylation motifs was found to induce a higher level of phosphorylation in epithelial

cells, which may therefore influence PD0325901 molecular weight the severity of the clinical outcomes (Argent et al., 2004). However, the detailed role of lipid rafts in membrane tethering of CagA remains to be elucidated. In this study, we investigated the effects of various CagA truncation mutants on the association between CagA and lipid rafts and on IL-8 induction. Our results provide evidence that the CagA C-terminal EPIYA-containing region is targeted to membrane rafts, which allows CagA-mediated induction of IL-8. Helicobacter pylori 26695 (ATCC 700392) was used as a reference strain and contains a cagA gene with three C-terminal EPIYA motifs (ABC-type) (Higashi et al., 2005). Clinical strain v669 was isolated from a patient with gastric cancer and contains a cagA gene with four C-terminal EPIYA motifs (AABD-type) (Lai et al., 2002). Helicobacter pylori strains

were recovered from frozen stocks on Brucella blood agar plates (Becton Dickinson). Construction of the cagA (∆CagA) and cagE (∆CagE) knockout strains were performed using the kanamycin resistance cassette (Kmr) from pACYC177 and the erythromycin resistance cassette (Eryr) from pE194, selleck inhibitor respectively, by the natural transformation method as we described previously (Lai et al., 2008). PCR and western blot analysis were employed to confirm the correct insertion of antibiotic resistance cassettes into the target genes. Various expression constructs encoding CagA truncation mutants were generated based on the H. pylori 26695 cagA sequence and v669 as illustrated in Fig. 3a. cagA fragments were amplified using PCR from H. pylori 26695 and v669 genomic DNA as described previously (Lai et al., DAPT 2002). The CagA-ΔN mutant

was generated from strain 26695 by amplification of sequence encoding amino acids 645–1186 using primers CagA-CTD59F and CagA-CTDR (Table 1). The primers used for PCR introduced a BamHI site at the 5′ end and an XbaI site at the 3′ end. The BamHI–XbaI fragment was then ligated into pEF1 expression vector (Invitrogen). Similar procedures were used to obtain the 669CagA-ΔN mutant from strain v669 using primers CagA-CTD59F and CagA-CTDR. To generate the CagA-ΔC mutant, a fragment encoding amino acids 1–358 was amplified using primers CagA1-F and CagA-1R. The primers used for PCR introduced a BamHI site at the 5′ end and an EcoRI site at the 3′ end. The BamHI–EcoRI fragment was then inserted into pEF1 to derive pEF1-CagA1. A fragment encoding amino acids 357–707 was amplified using primers CagA2F and CagA2R.

1a and b); K pneumoniae isolates displayed a higher number

1a and b); K. pneumoniae isolates displayed a higher number CHIR-99021 in vivo of CrR isolates with a cutoff MIC value at ≥ 0.8 mM chromate (Fig. 1c). No isolates in the Salmonella sp. group were considered as CrR because all of them showed a single MIC value of 0.4 mM chromate (Fig. 1d). Using these criteria, 23 isolates (21.1%) were classified as chromate resistant (Table 1). The MIC distribution curve for mercury showed a clear bimodal susceptibility pattern: a group of HgS isolates with MICs of 25–50 μM HgCl2 and a group of HgR isolates with MICs at 300–400 μM HgCl2 (Supporting information, Fig. S1). The HgR group consisted of 39 isolates (35.8%; Table 1). MIC analysis showed that nearly one-half of the isolates (51/109)

were resistant to either chromate or mercury, whereas 11 isolates (10.1%) displayed resistance to both agents (Table 1). The proportion of HgR isolates was similar to that found in other collections of nosocomial bacteria

(ranging from 30% to 50%; Porter et al., 1982; Deredjian et al., 2011). Possible sources of chromate acting as selective factors in hospital settings are not recognizable. The mechanisms of selection of heavy-metal-resistance phenotypes within hospitals remain unclear (Porter et al., 1982; Yurieva et al., 1997), RG7422 cell line but the nosocomial use of metal derivatives (i.e. organomercurials, silver compounds) as antiseptics or disinfectants has been proposed as a selective factor. The majority of E. coli and Salmonella isolates were metal sensitive, whereas metal-resistant isolates predominated in K. pneumoniae (61.3% CrR; 48.4% HgR) (Table 1). Klebsiella pneumoniae isolates have been considered as reservoirs of antibiotic-resistance plasmids in hospital settings (Carattoli, 2009), which may be related to the high levels of resistance to metals observed in this species. Enterobacter cloacae GABA Receptor isolates had a different pattern: the majority were chromate sensitive (11.8% CrR), but exhibited the highest proportion (64.7%) of mercury resistance (Table 1). The presence of CrR genes in the nosocomial isolates was first screened by colony hybridization assays at high stringency, utilizing a probe designed from the

chrA gene from P. aeruginosa pUM505 plasmid (Ramírez-Díaz et al., 2011). Widespread distribution of pUM505-related chrA genes in a previous study with P. aeruginosa clinical isolates from México (Cervantes & Ohtake, 1988) suggested that utilization of such a probe might allow for the detection of chrA sequences in the current collection under the conditions employed. Hybridization signals were found in 20/23 (86.9%) of the CrR isolates (data not shown and Table 1), suggesting that the majority possessed a mechanism of resistance involving chromate efflux. chrA sequences were detected in isolates from three of the four bacterial species analyzed (Table 1), indicating wide distribution of chrA homologues in the enterobacterial collection.