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Background: Staphylococcus epidermidis is a commensal of human skin flora and a frequent causative micro-organism in prosthetic joint infections (PJIs). To date, no single marker has been identified to distinguish infecting strains from commensal S. epidermidis populations. Aim: To find possible genetic markers to distinguish between the two populations. Methods: Fifty S. epidermidis strains from patients with PJIswere analysed, 50 fromthe skin of healthy individuals (commensal strains) and 17 from the surgical field of patients undergoing primary arthroplasty. In these three groups the antimicrobial susceptibility profile, sequence type, biofilm formation, and virulence factors were studied. Strains from the surgical field have not been compared previously with strains from the other two groups. Findings: S. epidermidis strains from PJI patients were significantly more antibiotic resistant than commensal strains and surgical field strains. A wide variety of sequence types was found in commensal and surgical field strains. The predominant sequence type was ST2 and it was only present in PJI strains (44%). Differences in biofilm production did not differ between populations. Virulence genes sdrF and bhp, the complete ica operon, and the insertion sequence IS256 were significantly predominant in PJI strains. By contrast, embp and hld genes and the arginine catabolic mobile element (ACME) were more prevalent in commensal strains. Surgical field strains could be a valid control group to discriminate between infecting and commensal strains. Conclusion: A combination of characteristic features can differentiate between infecting and commensal S. epidermidis strains in PJI, whereas a single marker cannot. (C) 2020 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Urinary tract infections caused by extended-spectrum β-lactamase

[Aim] This study analyzed the virulence of several Acinetobacter baumannii strains expressing different resistance mechanisms using the Caenorhabditis elegans infection model., [Results] Strains susceptible/resistant to carbapenems (presenting class D (OXA-23, OXA-24), class B metallo-β-lactamase (MBL) (NDM-1), penicillin binding protein (PBP) altered and decreased expression of Omp 33–36 kDa) and isogenic A. baumannii strains susceptible/resistant to colistin (presenting loss of lipopolysaccharide (LPS) and pmrA mutations) were included to evaluate the virulence using the C. elegans infection model. The nematode killing assay, bacterial ingestion in worms, and bacterial lawn avoidance assay were performed with the Fer-15 mutant line. A. baumannii strains generally presented low virulence, showing no difference between carbapenem-resistant strains (expressing class D, MBLs, or altered PBP) and their isogenic susceptible strains. In contrast, the absence of the Omp 33–36 kDa protein in the knockout was associated with a decrease of virulence, and a significant difference was observed between colistin-resistant mutants and their susceptible counterpart when the mechanism of resistance was associated with the loss of LPS but not with its modification., [Conclusions] Resistance to carbapenems in A. baumannii associated with the production of OXA-type or NDM-type enzymes does not seem to affect their virulence in the C. elegans infection model. In contrast, the presence of Omp 33–36 kDa, and high level resistance to colistin related with the loss of LPS, might contribute with the virulence profile in A. baumannii., This work was supported by INSERM, the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) under Research Grant (2013) to PE, the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC) under travel grant to PE, and the Instituto de Salud Carlos III (ISCIII), Madrid, Spain under “Sara Borrell” Postdoctoral Contract CD12/00482 to DR and CD15/00017 to PE.

In this study, the plasmid content of clinical and commensal strains was analyzed and compared. The replicon profile was similar in both populations, except for L, M, A/C, and N (detected only in clinical strains) and HI1 (only in commensal strains). Although I1 and F were the most frequent replicons, only IncI1, sequence type 12 (ST12) was associated with bla CMY-2 in both populations. In contrast, the widespread resistant IncF plasmids were not linked to a single epidemic plasmid.

Background In high-income countries, shigellosis is mainly found in travellers to high-risk regions or in men who have sex with men (MSM). This study investigated the genomic characteristics and the features of antimicrobial resistance of MSM-associated Shigella flexneri and Shigella sonnei circulating in Barcelona, Spain, elucidating their connectivity with contemporaneous Shigella spp. from other countries. Methods Antimicrobial susceptibility, whole-genome sequencing, genomic characterization and phylogenetic analysis were performed in MSM-associated Shigella spp. recovered from 2015 to 2019. Reference genomes of MSM-associated Shigella spp. were included for contextualization and to determine their connection with international outbreaks. Results In total, 44 S. flexneri and 26 S. sonnei were identified among MSM. Overall, 80% showed resistance to azithromycin, 65.7% showed resistance to trimethoprim-sulphamethoxazole and 32.8% showed resistance to ciprofloxacin; 27.1% were resistant to all three antimicrobials. mphA and/or ermB, and qnrS and mutations in the quinolone resistance determining regions were found in the azithromycin- and ciprofloxacin-resistant isolates, respectively. Additionally, two isolates carried blaCTX-M-27. Single-nucleotide-polymorphism-based analysis revealed that the isolates were organized into different lineages, most of which were closely related to dominant MSM-associated lineages described previously in the UK and Australia. Conclusions This study investigated the circulation of lineages of S. flexneri and S. sonnei among MSM in Spain that were mainly resistant to first-/second-line oral treatments, and closely related to dominant MSM-associated lineages described previously in the UK and Australia. These data reinforce the urgent need for the implementation of public health measures focusing on the early detection and prevention of transmission of this emerging pathogen, which is contributing to the antimicrobial resistance crisis in sexually transmitted infections.

Proteus mirabilis is the second most common cause of urinary tract infections and is also an important cause of nosocomial infections. TEM-type and CTX-M-type extended-spectrum β-lactamases (ESBLs) are the most widely distributed in this bacterial species, but minor ESBLs such as the VEB-type have also been identified. The aim of this study was to analyze the genetic environment of the blaVEB-4 gene found in a P. mirabilis clinical isolate recovered in Spain. P. mirabilis N2231 showed resistance to penicillins, cephalosporins, and aminoglycosides, remaining susceptible to imipenem, cefoxitin, β-lactamases inhibitors, and quinolones. Southern blot analysis revealed that blaVEB-4 was located in the chromosome. Analysis of the blaVEB-4 genetic context revealed a 15 kb segment 98% identical to the multidrug resistance (MDR) region of a Salmonella genomic island 1 (SGI1), which included a class 1 integron belonging to the In104 family, previously described in blaVEB-6-producing P. mirabilis VB1248. blaVEB-4 wa...

Objectives Antimicrobial resistance genes (ARGs) can be transferred by means of mobile genetic elements, which play a critical role in the dissemination of resistance in the bacterial community. ARG transmission within mobile genetic elements has been reported in plasmids and transposons but less frequently in bacteriophages. Here, the bacteriophage fraction of seven human faecal samples was purified and deep-sequenced to detect the presence of ARGs in the phage particles. Methods Seven faecal samples (five from healthy individuals and two from a patient before and after receiving ciprofloxacin treatment) were used to extract phage DNA, which was purified and then sequenced in a MiSeq (Illumina). Generated reads were checked for quality and assembled, and then the generated contigs analysed with Kraken, PHASTER, VirSorter and Prokka. Some genes were also validated by quantitative PCR. Results Analysis of the purified phage DNA by Kraken identified from 4 to 266 viruses in the samples. The viral fraction corresponded mainly to the order Caudovirales, including phages from the Siphoviridae and Myoviridae families. Bacterial genes associated with antimicrobial resistance were detected in the viral DNA, as confirmed by quantitative PCR. Higher densities of ARG-carrying phage particles were observed in the post- versus pre-ciprofloxacin treatment sample. Conclusions The finding of ARGs in phage particles supports the description of phages as mobile elements contributing to the dissemination of bacterial antibiotic resistance and suggests ciprofloxacin treatment may play a role in the release of ARG-carrying particles, thereby increasing resistance.

Phage particles have emerged as elements with the potential to mobilise antibiotic resistance genes (ARGs) in different environments, including the intestinal habitat. This study aimed to determine the occurrence of ARGs in phage particles present in faecal matter and induced from strains isolated from faeces. Nine ARGs (bla(TEM), bla(CTX-M-1 group), bla(CTX-M-9 group), bla(OXA-48), qnrA, qnrS, mecA, sul1 and armA) were quantified by qPCR in the phage DNA fractions of 150 faecal samples obtained from healthy individuals who had not received antibiotic treatment or travelled abroad in the 3 months prior to sample collection. On the suspicion that the detected particles originated from bacterial flora, 82 Escherichia coli and Klebsiella pneumoniae isolates possessing at least one identified ARG (bla(TEM), bla(CTX-M-1 group), bla(CTX-M-9 group), armA, qnrA, qnrS and sul1) were isolated and their capacity to produce phage particles carrying these ARGs following induction was evaluated. Of 150 samples, 72.7% were positive for at least one ARG, with bla(TEM) and bla(CTX-M-9 group) being the most prevalent and abundant. Of the 82 isolates, 51 (62%) showed an increase in the number of copies of the respective ARG in the phage fraction following induction, with bla(TEM), bla(CTX-M-1 group), bla(CTX-M-9 group) and sul1 being the most abundant. Phages induced from the isolates were further purified and visualised using microscopy and their DNA showed ARG levels of up to 1010 gene copies/mL. This study highlights the abundance of phage particles harbouring ARGs and indicates that bacterial strains in the intestinal habitat could be source of these particles. (C) 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

This study describes the molecular characterization of an NDM-7 carbapenemase-producing Escherichia coli strain Ec188, recovered from a rectal swab of a male patient who had travelled to Pakistan before his hospitalization at the Hospital del Mar in Barcelona, Spain. The Ec188 isolate, assigned to a new multilocus sequence type ST679, was resistant to all beta-lactams, aminoglycosides (gentamicin, tobramycin, and with reduced susceptibility to amikacin), and ciprofloxacin. The bla

Proteus mirabilis is the second most common cause of urinary tract infections and is also an important cause of nosocomial infections. TEM-type and CTX-M-type extended-spectrum β-lactamases (ESBLs) are the most widely distributed in this bacterial species, but minor ESBLs such as the VEB-type have also been identified. The aim of this study was to analyze the genetic environment of the bla

OBJECTIVES To determine the frequency of selecting mutants resistant to ozenoxacin, a des-fluoro-(6)-quinolone active against pathogens involved in skin and skin structure infections, compared with levofloxacin and ciprofloxacin in quinolone-susceptible and -resistant Gram-positive cocci. METHODS Forty-nine quinolone-susceptible and -resistant Gram-positive cocci strains with different profiles of mutations in the quinolone resistance-determining region (QRDR) were examined to determine the frequency of selecting mutants resistant to ozenoxacin compared with levofloxacin and ciprofloxacin. MICs and mutations in the QRDR were determined by standard broth microdilution and PCR amplification and sequencing, respectively. RESULTS The mean resistance rates were 3.8 × 10(-9) (range

In vitro activity of ozenoxacin, a novel nonfluorinated topical (L. D. Saravolatz and J. Leggett, Clin. Infect. Dis. 37: 1210–1215, 2003) quinolone, was compared with the activities of other quinolones against well-characterized quinolone-susceptible and quinolone-resistant Gram-positive bacteria. Ozenoxacin was 3-fold to 321-fold more active than other quinolones. Ozenoxacin could represent a first-in-class nonfluorinated quinolone for the topical treatment of a broad range of dermatological infections.

The development of high-level daptomycin resistance (HLDR; MIC of ≥256 mg/liter) after exposure to daptomycin has recently been reported in viridans group streptococcus (VGS) isolates. Our study objectives were as follows: to know whether in vitro development of HLDR after exposure to daptomycin was common among clinical isolates of VGS and Streptococcus bovis ; to determine whether HLDR also developed during the administration of daptomycin to treat experimental endocarditis caused by the daptomycin-susceptible, penicillin-resistant Streptococcus mitis strain S. mitis 351; and to establish whether combination with gentamicin prevented the development of HLDR in vitro and in vivo. In vitro studies were performed with 114 VGS strains (mitis group, 92; anginosus group, 10; mutans group, 8; and salivarius group, 4) and 54 Streptococcus bovis strains isolated from 168 consecutive patients with infective endocarditis diagnosed between 1995 and 2010. HLDR was only observed after 24 h of exposure to daptomycin in 27% of the mitis group, including 27% of S. mitis isolates, 47% of S. oralis isolates, and 13% of S. sanguis isolates. In our experimental model, HLDR was detected in 7/11 (63%) and 8/12 (67%) isolates recovered from vegetations after 48 h of daptomycin administered at 6 mg/kg of body weight/24 h and 10 mg/kg/24 h, respectively. In vitro , time-kill experiments showed that daptomycin plus gentamicin was bactericidal against S. mitis 351 at tested concentrations of 0.5 and 1 times the MIC and prevented the development of HLDR. In vivo , the addition of gentamicin at 1 mg/kg/8 h to both daptomycin arms prevented HLDR in 21 out of 23 (91%) rabbits. Daptomycin plus gentamicin was at least as effective as vancomycin plus gentamicin. In conclusion, HLDR develops rapidly and frequently in vitro and in vivo among mitis group streptococci. Combining daptomycin with gentamicin enhanced its activity and prevented the development of HLDR in most cases.

The aim of this study was to characterize the resistance mechanisms and genetic relatedness of 21 carbapenem-resistant Acinetobacter baumannii blood isolates collected in Italy during a 1-year multicenter prospective surveillance study. Genes coding for carbapenemase production were identified by polymerase chain reaction (PCR) and sequencing. Pulsed-field gel electrophoresis (PFGE), multiplex PCRs for group identification, and multilocus sequence typing (MLST) were used to determine genetic relationships. Carbapenem resistance was consistently related to the production of oxacillinases, mostly the plasmid-mediated OXA-58 enzyme. Strains producing the OXA-23 enzyme (chromosomally mediated) were also detected. Seven PFGE clones were identified, some of which being related to international (ICL- I and ICL-II) or national clonal lineages. Multiplex PCRs identified 4 different groups (group 2 being dominant), further distinguishable in 6 sequence types by MLST. The heterogeneity of profiles highlights the diffusion of international and national clonal lineages in Italy. Continuous surveillance is needed for monitoring the spread of these worrisome strains equipped with multiple drug resistance mechanisms.

Trypanosoma cruzi, the causative agent of Chagas disease, is divided into six Discrete Typing Units (DTUs): TcI–TcVI. We aimed to identify T. cruzi DTUs in Latin-American migrants in the Barcelona area (Spain) and to assess different molecular typing approaches for the characterization of T. cruzi genotypes. Seventy-five peripheral blood samples were analyzed by two real-time PCR methods (qPCR) based on satellite DNA (SatDNA) and kinetoplastid DNA (kDNA). The 20 samples testing positive in both methods, all belonging to Bolivian individuals, were submitted to DTU characterization using two PCR-based flowcharts: multiplex qPCR using TaqMan probes (MTq-PCR), and conventional PCR. These samples were also studied by sequencing the SatDNA and classified as type I (TcI/III), type II (TcII/IV) and type I/II hybrid (TcV/VI). Ten out of the 20 samples gave positive results in the flowcharts: TcV (5 samples), TcII/V/VI (3) and mixed infections by TcV plus TcII (1) and TcV plus TcII/VI (1). By SatDNA sequencing, we classified the 20 samples, 19 as type I/II and one as type I. The most frequent DTU identified by both flowcharts, and suggested by SatDNA sequencing in the remaining samples with low parasitic loads, TcV, is common in Bolivia and predominant in peripheral blood. The mixed infection by TcV–TcII was detected for the first time simultaneously in Bolivian migrants. PCR-based flowcharts are very useful to characterize DTUs during acute infection. SatDNA sequence analysis cannot discriminate T. cruzi populations at the level of a single DTU but it enabled us to increase the number of characterized cases in chronically infected patients. Fil: Abras, Alba. Universidad de Barcelona; España. Universidad de Girona; España. Barcelona Centre for International Health Research; España Fil: Gállego, Montserrat. Universidad de Barcelona; España. Barcelona Centre for International Health Research; España Fil: Muñoz, Cármen. Hospital de la Santa Creu i Sant Pau; España. Universitat Autònoma de Barcelona; España Fil: Juiz, Natalia Anahí. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Ramirez Gomez, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Cura, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres” ; Argentina Fil: Tebar, Silvia. Universidad de Barcelona; España. Barcelona Centre for International Health Research; España Fil: Fernández Arévalo, Ana. Universidad de Barcelona; España. Barcelona Centre for International Health Research; España. Hospital de la Santa Creu i Sant Pau; España Fil: Pinazo, María Jesús. Barcelona Centre for International Health Research; España Fil: de la Torre, Leonardo. Barcelona Centre for International Health Research; España Fil: Posada, Elizabeth. Barcelona Centre for International Health Research; España Fil: Navarro, Ferran. Universitat Autònoma de Barcelona; España. Hospital de la Santa Creu i Sant Pau; España Fil: Espinal, Paula. Hospital de la Santa Creu i Sant Pau; España Fil: Ballart, Cristina. Universidad de Barcelona; España. Barcelona Centre for International Health Research; España Fil: Portús, Montserrat. Universidad de Barcelona; España Fil: Gascón, Joaquim. Barcelona Centre for International Health Research; España Fil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina

Acinetobacter baumannii is emerging as an important hospital pathogen, which can persist in the environment for extended periods of time. It is known to produce biofilms, a community of bacteria enclosed within a protective polymeric matrix.To establish whether the effect of biofilm formation by Acinetobacter baumannii may be associated with persistence in the hospital environment.The effect of biofilm formation on the survival of A. baumannii on dry surfaces was investigated in biofilm-forming compared to non-biofilm-forming strains. Survival assays were determined by viable counts of the cells inoculated on to glass cover slips and stored under controlled conditions of temperature and relative humidity.The survival times for the biofilm-forming strains were longer than for the non-biofilm-forming ones (36 vs 15 days, respectively, P0.001). Scanning and transmission electron microscopy studies showed a polysaccharide layer and appendages in the biofilm-forming strains, not in the non-biofilm forming ones.Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, increasing the probability of causing nosocomial infections and outbreaks.

et al., There is limited information on the role of penicillin-binding proteins (PBPs) in the resistance of Acinetobacter baumannii to β-lactams. This study presents an analysis of the allelic variations of PBP genes in A. baumannii isolates. Twenty-six A. baumannii clinical isolates (susceptible or resistant to carbapenems) from three teaching hospitals in Spain were included. The antimicrobial susceptibility profile, clonal pattern, and genomic species identification were also evaluated. Based on the six complete genomes of A. baumannii, the PBP genes were identified, and primers were designed for each gene. The nucleotide sequences of the genes identified that encode PBPs and the corresponding amino acid sequences were compared with those of ATCC 17978. Seven PBP genes and one monofunctional transglycosylase (MGT) gene were identified in the six genomes, encoding (i) four high-molecular-mass proteins (two of class A, PBP1a [ponA] and PBP1b [mrcB], and two of class B, PBP2 [pbpA or mrdA] and PBP3 [ftsI]), (ii) three low-molecular-mass proteins (two of type 5, PBP5/6 [dacC] and PBP6b [dacD], and one of type 7 (PBP7/8 [pbpG]), and (iii) a monofunctional enzyme (MtgA [mtgA]). Hot spot mutation regions were observed, although most of the allelic changes found translated into silent mutations. The amino acid consensus sequences corresponding to the PBP genes in the genomes and the clinical isolates were highly conserved. The changes found in amino acid sequences were associated with concrete clonal patterns but were not directly related to susceptibility or resistance to β-lactams. An insertion sequence disrupting the gene encoding PBP6b was identified in an endemic carbapenem-resistant clone in one of the participant hospitals., This work was partially supported by the Instituto de Salud Carlos III, Spanish Network for Research in Infectious Diseases (REIPI, RD06/0008), and FIS (PI080209). We are grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), which gave a PDEE grant to R.C. (protocol 4149/08-4). We acknowledge the funding of MICINN (BFU2009-09200) to J.A.A.

The production of extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae is the most prevalent resistance mechanism to third-generation cephalosporins. The aim of this study was to identify the ESBLs produced in Escherichia coli and Klebsiella pneumoniae clinical isolates from two hospitals of the Colombian Caribbean Region. A total of 30 clinical isolates of K. pneumoniae (21) and E. coli (9) ESBL-producers were collected in two hospitals from January, 2001 to June, 2003. Isoelectric point values were indicative of SHV-, and CTX-M-type beta-lactamases. PCR amplification and sequencing of SHV genes revealed that SHV-12 was the most prevalent ESBL followed by SHV-5, SHV-2a, the novel SHV-86 and CTX-M-12. There was a geographic distribution of two particular PFGE subtypes in these two distant hospitals. Clonal and horizontal dissemination of resistance was observed.

Based on imipenem resistance in an Acinetobacter genospecies 3 clinical isolate, we were able to identify, for the first time in this genomic species, a plasmid-encoded bla OXA-58 gene that was 100% homologous to the same gene in Acinetobacter baumannii .

A novel QnrB-like plasmid-mediated resistance determinant, QnrB19, was identified from an Escherichia coli clinical isolate from Colombia. Its gene was associated with an IS Ecp1 -like insertion element that did not act as a promoter for its expression. Using an in vitro model of transposition, we showed that the IS Ecp1 -like element was able to mobilize the qnrB19 gene.

In this study, we describe the molecular characterization of a plasmid-located bla NDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. bla NDM-1 was carried by a conjugative plasmid widespread among non- baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species.

OBJECTIVES Acinetobacter nosocomialis has increasingly been reported as an opportunistic pathogen causing nosocomial infections. Although it is more susceptible to all antimicrobial agents than Acinetobacter baumannii, MDR clinical isolates have also been described. In addition, several studies have shown a high percentage of resistance to colistin. Therefore, in the present study we investigated the mechanism of resistance to colistin in this microorganism. METHODS Colistin-resistant strains were selected from the original colistin-susceptible A. nosocomialis strain following multi-step mutant selection. Comparative genomic and proteomic analyses of both colistin-susceptible and colistin-resistant A. nosocomialis strains were performed. In addition, virulence was investigated using the Caenorhabditis elegans assay. RESULTS The colistin-resistant mutants selected showed a lower resistance profile for other types of antibacterial agents together with a significant decrease in virulence. The LT50 (i.e. time required to kill 50% of the nematodes) for the colistin-susceptible strain (WT) was 7 days compared with 9 days for the colistin-resistant strain (256) (P

Resistance of Acinetobacter baumannii clinical isolates to carbapenems is on the rise worldwide mainly in association with the production of OXA-23. Until recently, however, OXA-23 was absent in Spain. In this work, we report the molecular characterization of a hospital outbreak of OXA-23-producing A. baumannii in Barcelona caused by a multidrug-resistant (MDR) clone belonging to international clone IC-II/sequence type ST85 between October 2010 and May 2011. bla OXA-23 was carried in a plasmid of 90 kb and located within the composite transposon Tn 2006 .

A carbapenem-resistant Acinetobacter baumannii clinical isolate belonging to European clone II and sequence type 2 was recovered from a patient in the Son Espases hospital in Mallorca, Spain. Genetic analysis showed the presence of the bla OXA-23 gene in association with the widely disseminated transposon Tn 2006 . This is the first reported identification of A. baumannii carrying bla OXA-23 in Spain.

New Delhi metallo-β-lactamase (NDM-1) was initially identified in various Enterobacteriaceae and recently in Acinetobacter baumannii . This study described the clonal dissemination of an NDM-2-producing A. baumannii isolate in an Israeli rehabilitation ward and the genetic surroundings of the gene. The bla NDM-2 gene was surrounded by the ble and trpF genes downstream and two copies of the IS Aba125 on both sides. These are the first NDM-producing A. baumannii strains in Israel from patients with no previous travel or hospitalization on the Indian subcontinent.

Acinetobacter baumannii is a multiresistant opportunistic nosocomial pathogen responsible for outbreaks worldwide. The main infection caused by this microorganism is nosocomial pneumonia, in particular ventilator-associated pneumonia in patients in Intensive Care Units. Treatment of these nosocomial infections is becoming problematic because the level of resistance to antimicrobial agents is rising. Ceftobiprole is a new cephalosporin with activity against Gram-positive and Gram-negative pathogens. This study evaluated the in vitro activity of ceftobiprole against a collection of 58 A. baumannii clinical isolates and showed that the activity of ceftobiprole was superior to ceftazidime and cefepime when the bla(ADC)-like gene was not expressed or was expressed at a low level.

The bla(OXA-58) gene identified in the Acinetobacter phenon 6/ct13TU clinical isolate presented 100% homology with the same gene in Acinetobacter baumannii. Its location in a plasmid suggests that these resistance genes may be transferred from 1 species to another.

Recently, different bacteriological laboratory interventions that decrease reporting time have been developed. These promising new broad-based techniques have merit, based on their ability to identify rapidly many bacteria, organisms difficult to grow or newly emerging strains, as well as their capacity to track disease transmission. The benefit of rapid reporting of identification and/or resistance of bacteria can greatly impact patient outcomes, with an improvement in the use of antibiotics, in the reduction of the emergence of multidrug resistant bacteria and in mortality rates. Different techniques revolve around mass spectrometry (MS) technology: matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), PCR combined with electrospray ionization-mass spectrometry (PCR/ESI-MS), iPLEX MassArray system and other new evolutions combining different techniques. This report emphasizes the (r)evolution of these technologies in clinical microbiology.

During the past few decades Acinetobacter baumannii has evolved from being a commensal dweller of health-care facilities to constitute one of the most annoying pathogens responsible for hospitalary outbreaks and it is currently considered one of the most important nosocomial pathogens. In a prevalence study of infections in intensive care units conducted among 75 countries of the five continents, this microorganism was found to be the fifth most common pathogen. Two main features contribute to the success of A. baumannii: (i) A. baumannii exhibits an outstanding ability to accumulate a great variety of resistance mechanisms acquired by different mechanisms, either mutations or acquisition of genetic elements such as plasmids, integrons, transposons, or resistant islands, making this microorganism multi- or pan-drug-resistant and (ii) The ability to survive in the environment during prolonged periods of time which, combined with its innate resistance to desiccation and disinfectants, makes A. baumannii almost impossible to eradicate from the clinical setting. In addition, its ability to produce biofilm greatly contributes to both persistence and resistance. In this review, the pathogenesis of the infections caused by this microorganism as well as the molecular bases of antibacterial resistance and clinical aspects such as treatment and potential future therapeutic strategies are discussed in depth.

Clin Microbiol Infect ABSTRACT: The closely related members of the Acinetobacter baumannii (Ab) group (A. baumannii, A. pittii and A. nosocomialis) are difficult to identify with phenotypic tests in diagnostic laboratories. Genotypic identification methods require special skills and most do not provide rapid results. The aim of this study was to investigate the ability of MALDI-TOF MS to identify members of the Ab group. Sixty epidemiologically unrelated Acinetobacter spp. isolates were investigated by MALDI-TOF MS: 18 A. baumannii, 17 A. pittii, 18 A. nosocomialis and seven additional isolates representing other Acinetobacter spp. All strains were verified by ARDRA, rRNA intergenic spacer (ITS), recA sequencing and bla(OXA-51) . MALDI-TOF MS correctly identified all the genomic strains but erroneously identified A. nosocomialis as A. baumannii because there was no reference strain within the Bruker database. Peak analysis of individual spectra from representative strains of each member of A. baumannii, A. pittii and A. nosocomialis suggested enough differences between their protein signatures to allow accurate identification using MALDI-TOF MS. Inclusion of specific signature profiles for A. nosocomialis within the Bruker database allowed the correct identification of this genomic species. MALDI-TOF MS spectra can be used as a fast, simple and reliable method to identify members of the Ab group. The rapid and accurate identification of clinically significant Acinetobacter strains will improve insight into their epidemiology and allow for targeted therapeutic and infection control measures against clinically important strains.

Species of Acinetobacter other than Acinetobacter baumannii are involved in nosocomial infections. Acinetobacter lwoffii, Acinetobacter genomospecies 3 and Acinetobacter genomospecies 13TU are found in community- and nosocomial-acquired infections as well as in neonatal intensive care units. The non-baumannii Acinetobacter are normally highly susceptible to ciprofloxacin, ampicillin/sulbactam, gentamicin and tigecycline. Carbepenems show good activity although resistant isolates have been reported. Resistance to β-lactams other than carbapenems is associated with overexpression of chromosomal cephalosporinases and extended-spectrum β-lactamase acquisition, whereas resistance to carbapenems involves acquisition of carbapenemases. Quinolone resistance is related to gyrA and/or parC mutations but overexpresion of efflux proteins also plays an important role. With the development of novel and more accurate typing methodologies, an increase in infections caused by non-baumannii Acinetobacter might be observed in the future.

Non- Acinetobacter baumannii spp. are emerging among clinical Acinetobacter isolates causing nosocomial infections, and some (such as genomospecies 13TU) appear to be multidrug resistant. The prevalence of non- Acinetobacter baumannii spp. in the hospital setting is likely understated due to poor identification techniques. We report the first identification of an AdeABC-type efflux pump in an Acinetobacter genomospecies 13TU clinical isolate, its contribution to multidrug resistance, and the coexistence of three Ade-type efflux pumps in this strain.

The scavenger receptor cysteine-rich superfamily (SRCR-SF) members are transmembrane and/or secreted receptors exhibiting one or several repeats of a cysteine-rich protein module of ∼100 aa, named scavenger receptor cysteine-rich (SRCR). Two types of SRCR domains (A or B) have been reported, which differ in the number of coding exons and intradomain cysteines. Although no unifying function has been reported for SRCR-SF members, recognition of pathogen-associated molecular patterns (PAMPs) was recently shown for some of them. In this article, we report the structural and functional characterization of mouse S5D-SRCRB, a new group B member of the SRCR-SF. The s5d-srcrb gene maps at mouse chromosome 7 and encompasses 14 exons extending over 15 kb. The longest cDNA sequence found is 4286 bp in length and encodes a mature protein of 1371 aa, with a predicted Mr of 144.6 kDa. Using an episomal mammalian-expression system, a glycosylated soluble recombinant form >200 kDa was obtained and used as immunogen for the generation of specific rat mAbs. Subsequent immunohistochemical and real-time PCR analysis showed significant S5D-SRCRB expression in murine genitourinary and digestive tracts. S5D-SRCRB was shown to bind endogenous extracellular matrix proteins (laminin and galectin-1), as well as PAMPs present on Gram-positive and Gram-negative bacteria and fungi. PAMP binding by S5D-SRCRB induced microbial aggregation and subsequent inhibition of PAMP-induced cytokine release. These abilities suggest that S5D-SRCRB might play a role in the innate defense and homeostasis of certain specialized epithelial surfaces.

Acinetobacter baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. baumannii strains, displaying strong substrate specificity toward chloramphenicol.

Pseudomonas aeruginosa ha emergido como uno de los principales patógenos hospitalarios causantes de infecciones graves y productores de β -lactamasas de espectro extendido (BLEE) inusuales, como PER- 1, OXA y carbapenemasas. Objetivo. Caracterizar los aislamientos de P. aeruginosa resistentes a -β -lactámicos de amplio espectro por investigación de los genotipos por rep- PCR y su diseminación en este hospital. Métodos. Se obtuvieron 26 aislamientos clínicos de P. aeruginosaresistentes a β -lact´micos de amplio espectro del Hospital San Jerónimo de enero a agosto del 2002. La resistencia a los β -lact´micos de amplio espectro se estableció con el sistema MicroScan® ESBL plusTM. Se utilizó la técnica de rep- PCR para la tipificación molecular de los microorganismos. Resultados. Los aislamientos mostraron resistencia a la fluoroquinolona ciprofloxacina (15/26, 57,6%) y aminoglucósidos, como gentamicina (14/ 26, 53,8%) y amikacina (9/26, 34,6%). También se observó resistencia a meropenem e imipenem (3/ 26, 11,5%). La tipificación molecular por rep-PCR mostró dos clones A y B de 15 y 3 aislamientos, respectivamente y 8 aislamientos no relacionados. El clon A con 15 aislamientos incluía dos subclones idénticos de 8 y 2 aislamientos, y 5 aislamientos estrechamente relacionadas. El clon B incluyó 3 aislamientos estrechamente relacionados con similaridad mayor del 90% Conclusiones. La relación de los fenotipos de resistencia expresados por estos aislamientos, posiblemente, indique la existencia de plásmidos de resistencia causantes de la infección hospitalaria en este hospital y responsables de codificar la resistencia a β-lact´micos de amplio espectro. Asimismo, el análisis molecular por rep-PCR mostró la diseminación de dos clones de P. aeruginosa en el hospital, de los cuales el clon A presentó aislamientos idénticos diseminados en diferentes servicios de la institución, lo que sugiere una transmisión horizontal.