The purpose of the study was to describe the microbiological and clinical features of ten cases of lower respiratory tract infection due to Corynebacterium striatum, Corynebacterium propinquum and Corynebacterium pseudodiphtheriticum. Respiratory samples were recovered from hospitalised patients who were diagnosed of pneumonia and exacerbations of chronic respiratory infections. The samples were Gram-stained and seeded on conventional bacterial growing media. Bacteria were identified by matrix-assisted linear desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility was tested by the disk diffusion method. All patients presented an acute respiratory onset, most of them in the context of an underlying disease and/or immunosuppression. In all patients, the microscopical examination of Gram-stained respiratory samples showed numerous polymorphonuclear cells and Gram-positive bacilli, suggestive of the Corynebacterium morphotype. A pure culture growth of Corynebacterium was obtained in the majority (72 %) of samples. The conclusions are that non-diphtheriae Corynebacterium species are an emerging cause of respiratory infection among patients with chronic respiratory disease and/or immunosuppression, and cannot always be considered as mere colonisers. The microorganism's predominance in Gram-stained purulent respiratory samples together with abundant growth in the culture is the key for the microbiological diagnosis.

Highlights Description of 4 cases outside Asia of invasive infection by hypervirulent K. pneumoniae. These are patients from the community without any type of epidemiological background or previous trips to the endemic area. Unlike other series in our case, these are patients without one of the classic risk factors: no patient is diabetic. Patients present both serotype K1 and K2, not finding a prevalent serotype in our series.

eThe antibacterial activity of fosfomycin-tobramycin combination was studied by time-kill assay in eight Pseudomonas aeruginosa clinical isolates belonging to the fosfomycin wild-type population (MIC ‫؍‬ 64 g/ml) but with different tobramycin susceptibilities (MIC range, 1 to 64 g/ml). The mutant prevention concentration (MPC) and mutant selection window (MSW) were determined in five of these strains (tobramycin MIC range, 1 to 64 g/ml) in aerobic and anaerobic conditions simulating environments that are present in biofilm-mediated infections. Fosfomycin-tobramycin was synergistic and bactericidal for the isolates with mutations in the mexZ repressor gene, with a tobramycin MIC of 4 g/ml. This effect was not observed in strains displaying tobramycin MICs of 1 to 2 g/ml due to the strong bactericidal effect of tobramycin alone. Fosfomycin presented higher MPC values (range, 2,048 to >2,048 g/ml) in aerobic and anaerobic conditions than did tobramycin (range, 16 to 256 g/ml). Interestingly, the association rendered narrow or even null MSWs in the two conditions. However, for isolates with high-level tobramycin resistance that harbored aminoglycoside nucleotidyltransferases, time-kill assays showed no synergy, with wide MSWs in the two environments. glpT gene mutations responsible for fosfomycin resistance in P. aeruginosa were determined in fosfomycin-susceptible wild-type strains and mutant derivatives recovered from MPC studies. All mutant derivatives had changes in the GlpT amino acid sequence, which resulted in a truncated permease responsible for fosfomycin resistance. These results suggest that fosfomycin-tobramycin can be an alternative for infections due to P. aeruginosa since it has demonstrated synergistic and bactericidal activity in susceptible isolates and those with low-level tobramycin resistance. It also prevents the emergence of resistant mutants in either aerobic or anaerobic environments.

Hepatitis E virus is responsible for sporadic cases of acute, self-limited viral hepatitis not only in endemic but also in industrialized countries. In addition, some reports confirm that it can cause chronic infection and even cirrhosis in immunosuppressed and also in patients infected with HIV. There are few data about prevalence and incidence of HEV chronic infection in HIV-HEV coinfected individuals in Spain. The aim of this study is to investigate the prevalence of anti-HEV IgG in a representative sample of 448 patients infected with HIV and determine the role of age, gender, and CD4 counts in the detection of anti-HEV IgG antibodies in blood. In addition, the clinical features and ALT levels in relation to the presence of anti-HEV IgM and/or HEV-RNA in the blood of these patients were investigated. Anti-HEV IgG antibodies were detected in serum using a commercial enzyme immunoassay. All positive samples were studied further for the presence of anti-HEV IgM antibodies. In addition, HEV RNA was amplified by reverse transcriptase (RT)-nested PCR in all serum samples with IgM anti-HEV. The overall prevalence of anti-HEV IgG was 10.4% (45/448, 95% C.I. 7.2-12.8%). HEV-RNA was found in only one patient out of the 45 anti-HEV IgG positive samples studied. Regarding to gender and CD4 count, no difference in seroprevalence could be observed. This prevalence data suggest that patients infected with HIV can be considered a risk group for HEV infection and that chronic coinfection HEV-HIV seems to be a very rare event.

The objective was to determine the in vitro antimicrobial susceptibility of Pseudomonas aeruginosa isolates cultured from cystic fibrosis (CF) patients and explore associations between strain sequence type and susceptibility. Fourteen antibiotics and antibiotic combinations, including the novel antibacterial peptide murepavadin, were tested for activity against 414 Pseudomonas aeruginosa isolates cultured from respiratory samples of CF patients. The complete genomes of the isolates were sequenced, and minimum spanning trees were constructed based on the sequence types (STs). Percentages of resistance according to CLSI 2019 breakpoints were as follows: cefepime, 14%; ceftazidime, 11%; ceftazidime-avibactam, 7%; ceftolozane-tazobactam, 3%; piperacillin-tazobactam, 12%; meropenem, 18%; imipenem, 32%; aztreonam, 23%; ciprofloxacin, 30%; gentamicin, 30%; tobramycin, 12%; amikacin, 18%; and colistin, 4%. Murepavadin MIC50 and MIC90 were 0.12 mg/liter and 2 mg/liter, respectively. There were no apparent clonal clusters associated with resistance, but higher MICs did appear to occur more often in STs with multiple isolates than in single ST isolates. In general, the CF isolates showed a wide genetic distribution. P. aeruginosa CF isolates exhibited the lowest resistance rates against ceftolozane-tazobactam, ceftazidime-avibactam, and colistin. Murepavadin demonstrated the highest activity on a per-weight basis and may therefore become a valuable addition to the currently available antibiotics for treatment of respiratory infection in people with CF.

The broth microdilution method for fosfomycin and Pseudomonas aeruginosa was assessed and compared with the approved agar dilution method in 206 genetically unrelated P. aeruginosa clinical isolates. Essential agreement between the two methods was 84%, and categorical agreement was 89.3%. Additionally, Etest and disk diffusion assays were performed. Results validate broth microdilution as a reliable susceptibility testing method for fosfomycin against P. aeruginosa. Conversely, unacceptable concordance was established between Etest and disk diffusion results with agar dilution results. Multi-drug resistance (MDR) in clinical Pseudomonas aeruginosa isolates has been widely reported and is of particularly concern in severe infections for which few therapeutic options remain available (1). Fosfomycin shows no cross-resistance with other antimicrobials and has demonstrated safety and efficacy over a broad range of infections and organisms (2). This antibiotic may act synergistically with many antimicrobials, and the intravenous form could be administered in combination for the treatment of systemic infections caused by MDR P. aeruginosa (3,4).The approved in vitro antimicrobial susceptibility testing method for fosfomycin is agar dilution (5); however, broth microdilution is the basis of automated systems currently used in clinical microbiology laboratories. Neither the Clinical and Laboratory Standards Institute (CLSI) (5) nor the European Committee on Antimicrobial Susceptibility Testing (EUCAST) (6) includes fosfomycin breakpoints for P. aeruginosa, although EUCAST has defined an epidemiological cutoff (ECOFF) value (6).Our study was designed to evaluate the in vitro fosfomycin activity against a collection of P. aeruginosa isolates by standard broth microdilution and to compare that method's performance with the performance of agar dilution, considered in this study as the reference method. In addition, agar dilution and broth microdilution were also assessed without glucose-6-phosphate (G6P) against 25 strains exhibiting different fosfomycin MIC values. Etest and disk diffusion were also assessed. A total of 206 genetically unrelated clinical P. aeruginosa isolates, 148 carbapenem susceptible and 58 non-carbapenem susceptible, were included (7). P. aeruginosa ATCC 27853 was used as the control.(Part of this research was presented at the 22nd European Congress of Clinical Microbiology and Infectious Diseases, London, United Kingdom, 31 March to 3 April 2012.) Susceptibility to fosfomycin (Laboratorios Ern, S.A., Barcelona, Spain) was determined concomitantly by agar dilution and broth microdilution using BBL Mueller-Hinton II cation-adjusted agar and broth, respectively (Becton, Dickinson [BD], Sparks, MD), both supplemented with 25 g/ml of G6P (SigmaAldrich Chemical Co., St. Louis, MO). The MIC was defined as the lowest antibiotic concentration that inhibited visible growth of the organism. MIC interpretation was done using an ECOFF value of Յ128 g/ml (6). Fosfomycin disk diffusion using disks of two different ...

Non-fermenting Gram negative bacteria are increasingly being cultured in respiratory samples from people with cystic fibrosis (CF). This study aimed to determine the susceptibility of clinical CF respiratory isolates from distinct geographical regions to a range of antimicrobials. A total of 286 isolates (106 Stenotrophomonas maltophilia, 100 Burkholderia spp., 59 Achromobacter spp., 12 Pandoraea spp. and 9 Ralstonia spp.) from The Netherlands, Northern Ireland, Spain, USA and Australia were tested. The MIC, MIC and susceptibility categorization were determined. Cotrimoxazole was the most active compound for all the microorganisms (MIC=0.12-4 mg/L, MIC=1-16 mg/L). For S. maltophilia, 47% and 62% of isolates were susceptible to cotrimoxazole according to CLSI and EUCAST breakpoints, respectively. Ceftazidime presented a lower level of susceptibility (35%, MIC=32 mg/L, MIC=256 mg/L). Tobramycin and colistin MIC were >128 mg/L and >16 mg/L, respectively. Regarding Burkholderia isolates, 72%, 56% and 44% were susceptible to cotrimoxazole, ceftazidime and meropenem, respectively. For both ceftazidime and meropenem, the MIC and MIC values were within the intermediate or resistant category. The most active antibiotics for A. xylosoxidans were cotrimoxazole (MIC=2, MIC=8 mg/L) and imipenem (MIC=2, MIC=8 mg/L). Cotrimoxazole, imipenem, and ciprofloxacin were active against the 12 Pandoraea species (MIC= 0.12-4 mg/L, MIC= 1-8 mg/L). Ciprofloxacin (MIC=4 mg/L) and cotrimoxazole (MIC=1 mg/L) were the only active antibiotics for Ralstonia spp. There were no statistically significant differences in susceptibility rates between countries. Non-fermenting Gram-negative bacteria other than P. aeruginosa are potential pathogens in CF and cotrimoxazole has demonstrated to be the most active compound against them.

Background Murepavadin, a novel peptidomimetic antibiotic, is being developed as an inhalation therapy for treatment of Pseudomonas aeruginosa respiratory infection in people with cystic fibrosis (CF). It blocks the activity of the LptD protein in P. aeruginosa causing outer membrane alterations. Objectives To determine the in vitro activity of murepavadin against CF P. aeruginosa isolates and to investigate potential mechanisms of resistance. Methods MIC values were determined by both broth microdilution and agar dilution and results compared. The effect of artificial sputum and lung surfactant on in vitro activity was also measured. Spontaneous mutation frequency was estimated. Bactericidal activity was investigated using time–kill assays. Resistant mutants were studied by WGS. Results The murepavadin MIC50 was 0.125 versus 4 mg/L and the MIC90 was 2 versus 32 mg/L by broth microdilution and agar dilution, respectively. Essential agreement was >90% when determining in vitro activity with artificial sputum or lung surfactant. It was bactericidal at a concentration of 32 mg/L against 95.4% of the strains within 1–5 h. Murepavadin MICs were 2–9 two-fold dilutions higher for the mutant derivatives (0.5 to >16 mg/L) than for the parental strains. Second-step mutants were obtained for the PAO mutS reference strain with an 8×MIC increase. WGS showed mutations in genes involved in LPS biosynthesis (lpxL1, lpxL2, bamA2, lptD, lpxT and msbA). Conclusions Murepavadin characteristics, such as its specific activity against P. aeruginosa, its unique mechanism of action and its strong antimicrobial activity, encourage the further clinical evaluation of this drug.