Auranofin efficacy against MDR Streptococcus pneumoniae and Staphylococcus aureus infections.

J Antimicrob Chemother. 2015 Jul 4. pii: dkv163. [Epub ahead of print]

Auranofin efficacy against MDR Streptococcus pneumoniae and Staphylococcus aureus infections.

Aguinagalde L1, Díez-Martínez R2, Yuste J3, Royo I4, Gil C5, Lasa Í5, Martín-Fontecha M6, Marín-Ramos NI7, Ardanuy C8, Liñares J8, García P2, García E2, Sánchez-Puelles JM9.

Author information

Abstract

BACKGROUND:

Auranofin is an FDA-approved, gold-containing compound in clinical use for the oral treatment of rheumatoid arthritis and has been recently granted by the regulatory authorities due to its antiprotozoal properties.

METHODS:

A reprofiling strategy was performed with a Streptococcus pneumoniae phenotypic screen and a proprietary library of compounds, consisting of both FDA-approved and unapproved bioactive compounds. Two different multiresistant S. pneumoniae strains were employed in a sepsis mouse model of infection. In addition, an MRSA strain was tested using both the thigh model and a mesh-associated biofilm infection in mice.

RESULTS:

The repurposing approach showed the high potency of auranofin against multiresistant clinical isolates of S. pneumoniae and Staphylococcus aureus in vitro and in vivo. Efficacy in the S. pneumoniae sepsis model was obtained using auranofin by the oral route in the dose ranges used for the treatment of rheumatoid arthritis. Thioglucose replacement by alkyl chains showed that this moiety was not essential for the antibacterial activity and led to the discovery of a new gold derivative (MH05) with remarkable activity in vitro and in vivo.

CONCLUSIONS:

Auranofin and the new gold derivative MH05 showed encouraging in vivo activity against multiresistant clinical isolates of S. pneumoniae and S. aureus. The clinical management of auranofin, alone or in combination with other antibiotics, deserves further exploration before use in patients presenting therapeutic failure caused by infections with multiresistant Gram-positive pathogens. Decades of clinical use mean that this compound is safe to use and may accelerate its evaluation in humans.

© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

PMID: 26142477 [PubMed - as supplied by publisher]

Multidrug-Resistant Streptococcus pneumoniae Isolates from Healthy Ghanaian Preschool Children.

Microb Drug Resist. 2015 Jul 14. [Epub ahead of print]

Multidrug-Resistant Streptococcus pneumoniae Isolates from Healthy Ghanaian Preschool Children.

Dayie NT1,2, Arhin RE1, Newman MJ1, Dalsgaard A2, Bisgaard M2, Frimodt-Møller N3, Slotved HC4.

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Abstract

Streptococcus pneumoniae is the cause of high mortality among children worldwide. Antimicrobial treatment and vaccination are used to control pneumococcal infections. In Ghana, data on antimicrobial resistance and the prevalence of multidrug-resistant pneumococcal clones are scarce; hence, the aim of this study was to determine the antibiogram of S. pneumoniae recovered from Ghanaian children younger than six years of age and to what extent resistances were due to the spread of certain sero- and multilocus sequence typing (MLST) types. The susceptibility of 115 pneumococcal isolates, recovered in a previous study, to six antimicrobials was determined by disk diffusion test. Overall, 90.4% of isolates were intermediate penicillin resistant, 99.1% were trimethoprim resistant, 73.0% were tetracycline resistant, and 33.9% were sulfamethoxazole resistant. Low resistance was recorded for erythromycin (2.6%) and cefotaxime (5.2%). Overall, 72.2% of isolates were resistant to penicillin (I or R) and at least two other antimicrobials. MLST of 20 isolates showing resistance to at least four antimicrobials revealed a high diversity documented by 16 different clones, none of which had previously been associated with multidrug resistance. The resistances found may have emerged due to nonprudent antimicrobial use practices and there is a need to monitor and promote prudent antimicrobial usage in Ghana.

PMID: 26172078 [PubMed - as supplied by publisher]

Serotyping, Antibiotic Susceptibility and Related Risk Factors Aspects of Nasopharyngeal Carriage of Streptococcus pneumoniae in Healthy School Students.

Iran J Public Health. 2014 Sep;43(9):1284-90.

Serotyping, Antibiotic Susceptibility and Related Risk Factors Aspects of Nasopharyngeal Carriage of Streptococcus pneumoniae in Healthy School Students.

Mirzaei Ghazikalayeh H1, Moniri R2, Moosavi SG3, Rezaei M1, Yasini M1, Valipour M1.

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Abstract

BACKGROUND:

Streptococcus pneumoniae is an important problem worldwide and nasopharyngeal colonization plays significant role in pneumococcal infections. The aims of this study were to determine the nasopharyngeal colonization rate, serotyping, antibiotics susceptibility and study the risk factors for nasopharyngeal colonization with S. pneumoniae in students in Kashan, Iran.

METHODS:

A cross-sectional study was conducted on children aged 7 to 19 years from December 2011 to November 2012. Nasopharyngeal swabs were plated onto brain heart infusion agar plates with 5% sheep blood and 4µg/ml of gentamycin. Antimicrobial susceptibility profiles were determined on Mueller-Hinton agar in accordance with CLSI. S. pneumoniae strains were investigated for the presence of the most common pneumococcal serotypes using a multiplex polymerase chain reaction.

RESULTS:

13.9% were found to be carriers. The most prevalent serogroups were 19F (30%), 6A/B (18.9%), 15A (16.5%), 11 (11.3%), 23F (8.2%), 1 (6.2%), 19A (3.4%), and 35B (2.4%). Nine strains (3.1%) were non-typeable. The carrier rate was significantly higher in 12 to15 year old age group. Upper respiratory tract infections within the last month (OR=1.5, P<0.011), previous hospitalization (OR=1.6, P<0.001), previous antibiotic usage last two weeks (OR=1.89, P<0.001), rhinorea (OR=1.9 P<0.001), male sex (OR=3.5 P< 0.001) and passive smoking (OR=1.56, P< 0.001) have been determined to be risk factors for S. pneumoniae carriage. The highest pneumococcal resistance was to tetracycline (25.4%). All strains were susceptible to linezolid and levofloxacin.

CONCLUSION:

Our information leads to an important source to screen the future impact of pneumococcal vaccination on bacterial colonization.

KEYWORDS:

Antibiotic resistance; Nasopharygeal; Serogroup; Streptococcus pneumoniae

PMID: 26175983 [PubMed] PMCID: PMC4500431 

Induced tigecycline resistance in Streptococcus pneumoniae mutants reveals mutations in ribosomal proteins and rRNA.

J Antimicrob Chemother. 2015 Jul 16. pii: dkv211. [Epub ahead of print]

Induced tigecycline resistance in Streptococcus pneumoniae mutants reveals mutations in ribosomal proteins and rRNA.

Lupien A1, Gingras H1, Leprohon P1, Ouellette M2.

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Abstract

OBJECTIVES:

Tigecycline is a broad-spectrum antibiotic acting at the level of the 30S ribosomal subunit to inhibit translation. While Streptococcus pneumoniae remains susceptible to tigecycline, resistance is beginning to emerge in some species and mainly involves efflux or mutations in ribosome constituents. We describe here the characterization of S. pneumoniae mutants selected for resistance to tigecycline.

METHODS:

Molecular determinants of resistance to tigecycline in S. pneumoniae were studied through WGS of two series of mutants made resistant to tigecycline in vitro in a stepwise fashion and by reconstructing tigecycline resistance using DNA transformation.

RESULTS:

The tigecycline-resistant S. pneumoniae M1TGC-6 and M2TGC-6 mutants were cross-resistant to tetracycline and minocycline. A role in tigecycline resistance could be attributed to 4 of the 12 genes that were mutated in both mutants. Mutations in ribosomal proteins S10 and S3, acquired early and late during selection, respectively, were implicated in resistance in both mutants. Similarly, mutations were detected in the four alleles of the 16S ribosomal RNA at sites involved in tigecycline binding and the number of mutated alleles correlated with the level of resistance. Finally, the gene spr1784 encodes an RsmD-like 16S rRNA methyltransferase for which inactivating mutations selected in the S. pneumoniae tigecycline-resistant mutants were found to decrease susceptibility to tigecycline.

CONCLUSIONS:

This first report about tigecycline resistance mechanisms in S. pneumoniae revealed that, in contrast to Gram-negative species, for which efflux appears central for tigecycline resistance, resistance in the pneumococcus occurs through mutations related to ribosomes.

© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

PMID: 26183184 [PubMed - as supplied by publisher]

Antibiotic resistance of Streptococcus pneumoniae colonizing the nasopharynx of HIV-exposed Tanzanian infants.

Trop Med Int Health. 2015 Jul 30. doi: 10.1111/tmi.12582. [Epub ahead of print]

Antibiotic resistance of Streptococcus pneumoniae colonizing the nasopharynx of HIV-exposed Tanzanian infants.

Bles P1, de Mast Q2,3, van der Gaast-de Jongh CE1,2, Kinabo GD4, Kibiki G5, van de Ven A2,3, de Jonge MI1,2.

Author information

Abstract

OBJECTIVES:

To determine antibiotic susceptibility of colonizing pneumococcal serotypes in HIV-exposed infants before the introduction of the 13-valent Pneumococcal Conjugate Vaccine (PCV13), because HIV-exposed infants are at increased risk for invasive pneumococcal infections.

METHODS:

Antibiotic susceptibility of 104 pneumococcal isolates, cultured from the nasopharynx from Tanzanian HIV-exposed infants, was determined using the disk diffusion method and the E-test according to EUCAST version 4.0 (2014) criteria.

RESULTS:

69.2% of isolates were intermediately susceptible for benzyl penicillin (MIC 0.06 - 2 mg L-1); no high level resistance was found. All isolates but one were susceptible to ampicillin. Regarding non-beta-lactam antibiotics, 19.2% of isolates were resistant to doxycycline, 3.8% to erythromycin and 97.1% to trimethoprim/sulfamethoxazole. 15.4% of isolates were resistant to three antibiotic classes or more. There were no differences in antibiotic susceptibility between vaccine and non-vaccine serotypes. Reduced susceptibility of colonizing pneumococcal isolates for commonly used antibiotics is common in HIV-exposed Tanzanian infants.

CONCLUSIONS:

High dose penicillin and ampicillin remain appropriate first choices for non-meningeal pneumococcal infections in this group. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

KEYWORDS:

Streptococcus pneumoniae ; Colonization; HIV-exposed infants; Tanzania; antibiotic resistance

PMID: 26224321 [PubMed - as supplied by publisher]

Impact of the Pneumococcal Conjugate Vaccine and Antibiotic Use on Nasopharyngeal Colonization by Antibiotic Nonsusceptible Streptococcus pneumoniae - Alaska, 2000-2010

Pediatr Infect Dis J. 2015 Jul 29. [Epub ahead of print]

Impact of the Pneumococcal Conjugate Vaccine and Antibiotic Use on Nasopharyngeal Colonization by Antibiotic Nonsusceptible Streptococcus pneumoniae - Alaska, 2000-2010.

Gounder PP1, Brewster M, Bruce MG, Bruden DJ, Rudolph K, Hurlburt DA, Hennessy TW.

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Abstract

BACKGROUND:

We describe the relative impact of the heptavalent pneumococcal conjugate vaccine (PCV7, introduced 2001) and antibiotic use on colonization by antibiotic resistant pneumococci in urban Alaskan children during 2000-2010.

METHODS:

We obtained nasopharyngeal swab specimens from a convenience sample of children aged <5 years at clinics annually during 2000-2004 and 2008-2010. PCV7 status and antibiotic use <90days before enrollment was determined by interview/medical records review.Pneumococci were characterized by serotype and susceptibility to penicillin (PCN). Isolates with full PCN resistance (PCN-R) or intermediate PCN resistance (PCN-I) were classified as PCN-NS.

RESULTS:

We recruited 3,496 children (median: 452/year). During 2000-2010, a range of 18-29%/year of children used PCN/amoxicillin (p-value for trend [p] = 0.09); the proportion age-appropriately vaccinated with PCV7 increased (0%-90%; p <0.01). Among pneumococcal isolates, the PCV7-serotype proportion decreased (53%-<1%; p <0.01) and non-PCV7-serotype proportion increased (43%-95%; p <0.01). PCN-R pneumococcal colonizationprevalence decreased (23%-9%, p <0.01) and PCN-I pneumococcal colonization prevalence increased (13%-24%, p <0.01); overall PCN-NS pneumococcalcolonizationprevalence was unchanged. PCN-NS among colonizing PCV7-type and non-PCV7-type pneumococci remained unchanged; a mean of 31%/year of PCV7-type and 10%/year of non-PCV7-type isolates were PCN-R, and 10%/year of PCV7 and 20%/year of non-PCV7-type isolates were PCN-I.

CONCLUSIONS:

Overall PCN-NS pneumococcal colonization remained unchanged during 2000-2010 because increased colonization by predominantly PCN-I non-PCV7 serotypes offset decreased colonization by predominantly PCN-R PCV7 serotypes. Proportion PCN-NS did not increase within colonizing pneumococcal serotype-groups (PCV7 versus non-PCV7) despite stable penicillin use in our population.

PMID: 26226443 [PubMed - as supplied by publisher]

In vitro susceptibility of a penicillin-resistant and tolerable isolate of Streptococcus pneumoniae to combination therapy.

J Infect Dev Ctries. 2015 Jul 30;9(7):702-9. doi: 10.3855/jidc.4711.

In vitro susceptibility of a penicillin-resistant and tolerable isolate of Streptococcus pneumoniae to combination therapy.

Majhi A1, Nandi A, Adhikary R, Mahanti S, Bishayi B.

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Abstract

INTRODUCTION:

Preference for combination therapy to treat infection due to multidrug-resistant S. pneumoniae (MDRSP) has not been well elucidated in previous studies.

METHODOLOGY:

In the present study, 19 antibiotics in combinations were tested against an MDRSP isolate. In vitro susceptibility studies including minimum inhibitory concentration (MIC), minimal bactericidal concentrations (MBC) and disk agar diffusion (DAD), tolerance to resistant antibiotics, checkerboard assay, time-kill curve, hemolytic assay, and autolysis assay were performed on the test strain to study its in vitro susceptibility to combination therapy.

RESULTS:

From the checkerboard assay and time-kill curve, it was observed that a combination of levofloxacin (MIC, 16 µg/mL) and ceftriaxone (MIC, 2 µg/mL), at sub-MIC concentration was synergistic and most effective against the MDRSP isolate (penicillin MIC, > 64 µg/mL). Hemolytic activities also increased significantly with combination therapy compared to monotherapy (p < 0.05). Moreover, the hemolytic activity of levofloxacin in combination with ceftriaxone was better than ciprofloxacin plus ceftriaxone or cefepime. The autolysis rate was also found to increase rapidly within one hour of exposure to levofloxacin plus ceftriaxone, and this was found to be significantly different from the other combinations at the fifth and sixth hour post incubation (p < 0.05).

CONCLUSIONS:

This data suggests that this combination is bactericidal in vitro, and requires further studies in in vivo models for treatment against MDRSP infections.

PMID: 26230119 [PubMed - in process] 

Antimicrobial Susceptibility/Resistance of Streptococcus Pneumoniae.

Mater Sociomed. 2015 Jun;27(3):180-4. doi: 10.5455/msm.2015.27.180-184. Epub 2015 Jun 8.

Antimicrobial Susceptibility/Resistance of Streptococcus Pneumoniae.

Karcic E1, Aljicevic M2, Bektas S3, Karcic B4.

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Abstract

INTRODUCTION:

Pneumococcal infections are a major cause of morbidity and mortality worldwide, whose treatment is threatened with an increase in the number of strains resistant to antibiotic therapy.

GOAL:

The main goal of this research was to investigate the presence of antimicrobial susceptibility/resistance of S. pneumoniae.

MATERIAL AND METHODS:

Taken are swabs of the nose and nasopharynx, eye and ear. In vitro tests that were made in order to study the antimicrobial resistance of pneumococci are: disk diffusion method and E-test.

RESULTS:

The resistance to inhibitors of cell wall synthesis was recorded at 39.17%, protein synthesis inhibitors 19.67%, folate antagonists 47.78% and quinolone in 1.11%. S. pneumoniae has shown drug resistance to erythromycin in 45%, clindamycin in 45%, chloramphenicol-0.56%, rifampicin-6.11%, tetracycline-4.67%, penicillin-G in 4.44%, oxacillin in 73.89%, ciprofloxacin in 1.11% and trimethoprim-sulfamethoxazole in 5.34% of cases.

CONCLUSION:

The highest resistance pneumococcus showed to erythromycin, clindamycin and trimethoprim-sulfamethoxazole and these should be avoided in the treatment. The least resistance pneumococcus showed to tetracycline, rifampicin, chloramphenicol, penicillin-G and ciprofloxacin.

KEYWORDS:

antibiotics; pneumococcus; resistance; susceptibility

PMID: 26236165 [PubMed]

Transfer of penicillin resistance from Streptococcus oralis to Streptococcus pneumoniae identifies murE as resistance determinant.

Mol Microbiol. 2015 May 25. doi: 10.1111/mmi.13070. [Epub ahead of print]

Transfer of penicillin resistance from Streptococcus oralis to Streptococcus pneumoniae identifies murE as resistance determinant.

Todorova K1, Maurer P1, Rieger M1, Becker T1, Bui NK2, Gray J3, Vollmer W2, Hakenbeck R1.

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Abstract

Beta-lactam resistant clinical isolates of Streptococcus pneumoniae contain altered penicillin-binding protein (PBP) genes and occasionally an altered murM, presumably products of interspecies gene transfer. MurM and MurN are responsible for the synthesis of branched lipid II, substrate for the PBP catalyzed transpeptidation reaction. Here we used the high-level beta-lactam resistant S. oralis Uo5 as donor in transformation experiments with the sensitive laboratory strain S. pneumoniae R6 as recipient. Surprisingly, piperacillin resistant transformants contained no alterations in PBP genes but carried murEUo5 encoding the UDP-N-acetylmuramyl tripeptide synthetase. Codons 83-183 of murEUo5 were sufficient to confer the resistance phenotype. Moreover, the promoter of murEUo5 which drives a twofold higher expression compared to that of S. pneumoniae R6 could also confer increased resistance. Multiple independent transformations produced S. pneumoniae R6 derivatives containing murEUo5 , pbp2xUo5 , pbp1aUo5 and pbp2bUo5 , but not murMUo5 sequences; however, the resistance level of the donor strain could not be reached. S. oralis Uo5 harbors an unusual murM, and murN is absent. Accordingly, the peptidoglycan of S. oralis Uo5 contained interpeptide bridges with one L-Ala residue only. The data suggest that resistance in S. oralis Uo5 is based on a complex interplay of distinct PBPs and other enzymes involved in peptidoglycan biosynthesis.

This article is protected by copyright. All rights reserved.

KEYWORDS:

MurE; Penicillin-binding protein; Streptococcus oralis; Streptococcus pneumoniae; penicillin resistance

PMID: 26010014 [PubMed - as supplied by publisher]

Frequency of Spontaneous Resistance to Peptide Deformylase Inhibitor GSK1322322 in Haemophilus influenzae, Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae.

Antimicrob Agents Chemother. 2015 May 26. pii: AAC.00484-15. [Epub ahead of print]

Frequency of Spontaneous Resistance to Peptide Deformylase Inhibitor GSK1322322 in Haemophilus influenzae, Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae.

Min S1, Ingraham K2, Huang J2, McCloskey L2, Rilling S2, Windau A3, Pizzollo J2, Butler D2, Aubart K2, Miller LA2, Zalacain M2, Holmes DJ2, O'Dwyer K2.

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Abstract

The continuous emergence of multidrug resistant pathogenic bacteria is compromising the successful treatment of serious microbial infections. GSK1322322, a novel peptide deformylase (PDF) inhibitor, shows good in vitro antibacterial activity and has demonstrated safety and efficacy in human proof-of-concept clinical studies. In vitro studies were performed to determine the frequency of resistance (FoR) to this antimicrobial agent in major pathogens causing respiratory tract and skin infections. Resistance to GSK1322322 occurred at high frequency through loss-of-function mutations in the formyl-methionyl transferase (FMT) protein in Staphylococcus aureus (4/4 strains) and Streptococcus pyogenes (4/4 strains), and via missense mutations in Streptococcus pneumoniae (6/21 strains), but these mutations are associated with a severe in vitro and/or in vivo fitness cost. The overall FoR to GSK1322322 was very low in Haemophilus influenzae with only one PDF mutant identified in one of four strains. No target-based mutants were identified from S. pyogenes, and only one or no PDF mutants were isolated in three of the four S. aureus strains studied. In S. pneumoniae, PDF mutants were only isolated from six of 21 strains tested and an additional 10 strains did not yield colonies on GSK1322322-containing plates. Most of the PDF mutants characterized from these three organisms (35/37), carried mutations in residues at or in close proximity to one of three highly conserved motifs, which are part of the active site of the PDF protein, with 30 of the 35 mutations occurring at position V71 (S. pneumoniae numbering system).

Copyright © 2015, American Society for Microbiology. All Rights Reserved.

PMID: 26014938 [PubMed - as supplied by publisher]

Inclusion bodies and pH lowering: as an effect of gold nanoparticles in Streptococcus pneumoniae.

Metallomics. 2015 May 12. [Epub ahead of print]

Inclusion bodies and pH lowering: as an effect of gold nanoparticles in Streptococcus pneumoniae.

Ortiz-Benitez EA1, Carrillo-Morales M, Velázquez-Guadarrama N, Fandiño-Armas J, Olivares-Trejo JJ.

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Abstract

Streptococcus pneumoniae is a human pathogen whose principal virulence factor is its capsule. This structure allows the bacterium to evade the human immune system. Treatment of infections caused by this bacterium is based on antibiotics; however, the emergence of antibiotic-resistant strains makes this task increasingly difficult. Therefore, it is necessary to investigate new therapies, such as those based on gold nanoparticles, for which unfortunately the mechanisms involved have not yet been investigated. As far as we know, this study is the first that attempts to explain how gold nanoparticles destroy the bacterium Streptococcus pneumoniae. We found that the mean particle size was an important issue, and that the effect on the bacterium was dose-dependent. Cellular growth was inhibited by the presence of the nanoparticles, as was cell viability. The pH of the bacterial growth media was acidified, but interestingly the reactive species were not affected. A transmission electron microscopy analysis revealed the presence of inclusion bodies of gold nanoparticles within the bacterium. We present the first findings that attempt to explain how gold nanoparticles lyse Gram-positive bacteria.

PMID: 25966022 [PubMed - as supplied by publisher]

CXCL14 Displays Antimicrobial Activity against Respiratory Tract Bacteria and Contributes to Clearance of Streptococcus pneumoniae Pulmonary Infection.

J Immunol. 2015 May 11. pii: 1402634. [Epub ahead of print]

CXCL14 Displays Antimicrobial Activity against Respiratory Tract Bacteria and Contributes to Clearance of Streptococcus pneumoniae Pulmonary Infection.

Dai C1, Basilico P1, Cremona TP1, Collins P2, Moser B2, Benarafa C1, Wolf M3.

Author information

Abstract

CXCL14 is a chemokine with an atypical, yet highly conserved, primary structure characterized by a short N terminus and high sequence identity between human and mouse. Although it induces chemotaxis of monocytic cells at high concentrations, its physiological role in leukocyte trafficking remains elusive. In contrast, several studies have demonstrated that CXCL14 is a broad-spectrum antimicrobial peptide that is expressed abundantly and constitutively in epithelial tissues. In this study, we further explored the antimicrobial properties of CXCL14 against respiratory pathogens in vitro and in vivo. We found that CXCL14 potently killed Pseudomonas aeruginosa, Streptococcus mitis, and Streptococcus pneumoniae in a dose-dependent manner in part through membrane depolarization and rupture. By performing structure-activity studies, we found that the activity against Gram-negative bacteria was largely associated with the N-terminal peptide CXCL141-13. Interestingly, the central part of the molecule representing the β-sheet also maintained ∼62% killing activity and was sufficient to induce chemotaxis of THP-1 cells. The C-terminal α-helix of CXCL14 had neither antimicrobial nor chemotactic effect. To investigate a physiological function for CXCL14 in innate immunity in vivo, we infected CXCL14-deficient mice with lung pathogens and we found that CXCL14 contributed to enhanced clearance of Streptococcus pneumoniae, but not Pseudomonas aeruginosa. Our comprehensive studies reflect the complex bactericidal mechanisms of CXCL14, and we propose that different structural features are relevant for the killing of Gram-negative and Gram-positive bacteria. Taken together, our studies show that evolutionary-conserved features of CXCL14 are important for constitutive antimicrobial defenses against pneumonia.

Copyright © 2015 by The American Association of Immunologists, Inc.

PMID: 25964486 [PubMed - as supplied by publisher]

Characterization of MDR and XDR Streptococcus pneumoniae in Canada, 2007-13.

J Antimicrob Chemother. 2015 Apr 28. pii: dkv107. [Epub ahead of print]

Characterization of MDR and XDR Streptococcus pneumoniae in Canada, 2007-13.

Golden AR1, Rosenthal M2, Fultz B2, Nichol KA3, Adam HJ4, Gilmour MW5, Baxter MR2, Hoban DJ4, Karlowsky JA4, Zhanel GG2.

Author information

Abstract

OBJECTIVES:

The goal of this study was to characterize Streptococcus pneumoniae demonstrating MDR (resistant to three or more antimicrobial classes) or XDR (resistant to five or more classes) phenotypes, collected from Canada during the CANWARD 2007-13 study.

METHODS:

From 2007 to 2013 inclusive, S. pneumoniae isolates were collected as a part of the CANWARD surveillance study. MDR and XDR isolates were subjected to PFGE, MLST, molecular detection of pneumococcal pili and macrolide resistance determinants mef(A/E) and erm(B), sequencing of PBPs 1A, 2B and 2X and comparison with Pneumococcal Molecular Epidemiology Network (PMEN) clones.

RESULTS:

Of 2129 S. pneumoniae isolates collected during the CANWARD 2007-13 study, 61 (2.9%) were found to be MDR. Of these MDR isolates, 43 (70.5%) were XDR. The most common serotypes for both MDR and XDR S. pneumoniae were 19A and 19F. Twenty-nine of 61 isolates (48%) demonstrated resistance to clarithromycin, clindamycin, doxycycline, penicillin and trimethoprim/sulfamethoxazole. All isolates possessed at least one macrolide resistance determinant and mutations in PBPs 1A, 2B and 2X. The most common clone was piliated, XDR ST320, an internationally circulating double-locus variant of Taiwan19F-14 (ST236).

CONCLUSIONS:

Though the rate of MDR S. pneumoniae has remained relatively stable since 2007, XDR strains have emerged in Canada. These strains are virulent, possess resistance determinants and are related to international clones.

© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

KEYWORDS:

S. pneumoniae; extensively drug resistant; molecular characterization; multidrug resistant; resistance mechanisms

PMID: 25921512 [PubMed - as supplied by publisher]

Genetic analyses of PBP determinants in multidrug-resistant Streptococcus pneumoniae serogroup 19 CC320/271 clone with high level resistance to third generation cephalosporins.

Antimicrob Agents Chemother. 2015 Apr 27. pii: AAC.00094-15. [Epub ahead of print]

Genetic analyses of PBP determinants in multidrug-resistant Streptococcus pneumoniae serogroup 19 CC320/271 clone with high level resistance to third generation cephalosporins.

Ip M1, Ang I2, Liyanapathirana V2, Ma H2, Lai R2.

Author information

Abstract

We describe the dissemination of a multidrug resistant serogroup 19 pneumococcal clone with representative MLST type ST271 with high level resistance to cefotaxime in Hong Kong, the penicillin binding protein genes (pbp) and their relationships to the Taiwan19F-14 (PMEN14) and the prevalent multidrug resistant clone, MDR19A-ST320. A total of 472 non-duplicate isolates in 2006 and 2011 were analyzed. Significant increases in the non-susceptibility rates of PEN (MIC ≥4.0 μg/ml, 9.9 vs 23.3%, p=0.0005), CTX (MIC ≥2.0 μg/ml, 12.2 vs 30.3%, p<0.0001, and meningitis MIC ≥1.0 μg/ml, 30.2 vs 48.7%, p=0.0001) and ERY (69.2 vs 84.0%, p=0.0003) were noted. The CTX resistant isolates with MIC 8 μg/ml in 2011 were of serotype 19F, belonging to ST271. Analyses of the PBP2x a.a. sequences in relation to the corresponding sequences of R6 strain revealed substitutions at M339F, E378A, M400T, and Y595F found within ST271 clone but not present in Taiwan19F-14 or MDR19A. In addition, the PBP2b of ST271 strains and that of Taiwan19F-14 clone were characterized by a unique a.a. substitution at E369D, while ST320 possessed unique a.a. substitution K366N as that of MDR19A in the United States. We hypothesize that ST271 originated from Taiwan19F-14 lineage which had disseminated in Hong Kong in early 2000s, and conferred higher β-lactam and cefotaxime resistance through acquisitions of 19 additional a.a. substitutions in PBP2b (a.a. positions 538 to 641) and altered PBP2x via recombination events. The serogroup 19 MDR CC320/271 clone warrants close monitoring to evaluate its effect after the switch to the expanded conjugate vaccines.

Copyright © 2015, American Society for Microbiology. All Rights Reserved.

PMID: 25918136 [PubMed - as supplied by publisher] 

Penicillin-Resistant trend of Streptococcus pneumoniae in Asia: A systematic review.

Iran J Microbiol. 2014 Aug;6(4):198-210.

Penicillin-Resistant trend of Streptococcus pneumoniae in Asia: A systematic review.

Mamishi S1, Moradkhani S2, Mahmoudi S2, Hosseinpour-Sadeghi R2, Pourakbari B2.

Author information

Abstract

The high prevalence of resistance to penicillin by Streptococcus pneumoniaeis considered as a great concern, particularly in Asian countries. The aim of this study was to investigate the changing trend of penicillin-resistant S. pneumoniae (PRSP) in Asia over a 20 years period. A review of the literature was conducted using the PubMed database, Google Scholar, Scopus, two Persian scientific search engines "Scientific Information Database" (www.sid.ir), and "Mag Iran" (www.magiran.com) through 1993 to 2013. Our study provides a unique chance to investigate the changing trend in PSSP in Asia over a 20 years period. Susceptibility rates among different centers in each country varied widely. In Malaysia, the PSSP rate decreased from 97.2% in 1995-1996 to 69% in 2000. In Singapore, PSSP levels decreased from 72.6% in 1997 to 30.5% in 2007-2008. In Iran, PSSP ranged from 0% to 100%. In Taiwan, the rate of PSSP was 60.3% in 1995 and <50% in other years. In Lebanon, the rate of PSSP was less than 50% (ranging from 30.1% to 50%) in all published data. In Hong Kong, the level of penicillin susceptibility decreased from 71.1% during 1993-1995 to less 42% in 2007. Continuous surveillance of resistance data from clinical isolates as well as implementation of strict infection control policies is recommended. More studies are needed for better evaluation PSSP rate in some Asian countries such as Vietnam, Singapore, Philippines, Pakistan, Nepal, Kuwait, Korea and Indonesia.

KEYWORDS:

Asia; S. pneumoniae; penicillin resistant

PMID: 25802701 [PubMed] 

The Effect of Macrolide-Resistance on the Presentation and Outcome of Patients Hospitalized for Streptococcus pneumoniae Pneumonia.

Am J Respir Crit Care Med. 2015 Mar 25. [Epub ahead of print]

The Effect of Macrolide-Resistance on the Presentation and Outcome of Patients Hospitalized for Streptococcus pneumoniae Pneumonia.

Cilloniz C1, Albert RK, Liapikou A, Gabarrus A, Rangel E, Bello S, Marco F, Mensa J, Torres A.

Author information

Abstract

BACKGROUND:

There are conflicting reports describing the effect of macrolide resistance on the presentation and outcomes of patients with Streptococcus pneumoniae pneumonia.

METHODS:

We conducted a retrospective, observational study in the Hospital Clinic of Barcelona of all adult patients hospitalized with pneumonia who had positive cultures for S. pneumoniae from January 1, 2000 to December 31, 2013. Outcomes examined included bacteremia, pulmonary complications, acute renal failure, shock, intensive care unit admission, need for mechanical ventilation, length of hospital stay and 30-day mortality.

RESULTS:

Of 643 patients hospitalized for S. pneumoniae pneumonia, 139 (22%) were macrolide-resistant. Patients with macrolide-resistant organisms were less likely to have bacteremia, pulmonary complications and shock, and were less likely to require non-invasive mechanical ventilation. We found no increase in the incidence of acute renal failure, the frequency of ICU admission, the need for invasive ventilatory support, the length hospital stay or the 30-day mortality in patients with (invasive or non-invasive) macrolide-resistant S. pneumoniae pneumonia, and no effect on outcomes as a function of whether treatment regimens did or did not comply with current guidelines.

CONCLUSIONS:

We found no evidence suggesting that patients hospitalized for macrolide-resistant S. pneumoniae pneumonia had worse clinical outcomes.

KEYWORDS:

S. pneumoniae resistant to macrolide; community-acquired pneumonia; pneumococcal pneumonia; pneumonia

PMID: 25807239

In vitro activity of bioactive extracts from rare actinomycetes against multi-drug resistant Streptococcus pneumoniae.

J Appl Microbiol. 2015 Mar 21. doi: 10.1111/jam.12810. [Epub ahead of print]

In vitro activity of bioactive extracts from rare actinomycetes against multi-drug resistant Streptococcus pneumoniae.

Tiwari K1, Raj VS, Upadhyay DJ, Gupta RK.

Author information

Abstract

AIMS:

In this study, we investigated the in vitro potential of the bioactive extracts from five putatively novel species of actinomycetes isolated from the Indian hot desert against multi-drug resistant (MDR) Streptococcus pneumoniae.

METHODS AND RESULTS:

The antimicrobial activity of 10 different extracts was evaluated against S. pneumoniae strains with, erm(B) and mef(E) genes as well as fluoroquinolone-resistant (FQR ) strains using the micro-broth dilution method. Of these 10 extracts, four exhibited good to excellent anti-S. pneumoniae activity with minimum inhibitory concentrations (MICs) ranging from 0·125 to 8 μg ml-1 . The time-kill kinetics study showed that these extracts killed the pathogens in 2-8 h. In vitro cell-free transcription/translation of luciferase gene using S30 bacterial extract and TNT mammalian ribosome indicated that they inhibited bacterial ribosomes at much lower concentrations than those required to inhibit the mammalian ribosomes.

CONCLUSIONS:

This study demonstrates that these are potent concentration-dependent bactericidal metabolites with 16-fold higher in vitro activity than levofloxacin against MDR S. pneumoniae.

SIGNIFICANCE AND IMPACT OF THE STUDY:

Metabolites from actinomycetes can be excellent inhibitors of MDR S. pneumoniae. Considering the in vitro efficacy of these crude extracts against S. pneumoniae MDR spp., once purified these can be used against streptococcal pathogens causing community-acquired pneumonia.

© 2015 The Society for Applied Microbiology.

KEYWORDS:

S. pneumoniae ; antimicrobial susceptibility; bioactive extracts; multi-drug resistance; rare actinomycetes; time-kill kinetics

PMID: 25810118

Profiling of β-Lactam Selectivity for Penicillin-Binding Proteins in Streptococcus pneumoniae D39.

Profiling of β-Lactam Selectivity for Penicillin-Binding Proteins in Streptococcus pneumoniae D39.

Kocaoglu O1, Tsui HC2, Winkler ME3, Carlson EE4.

Author information

Abstract

Selective fluorescent β-lactam chemical probes enable the visualization of the transpeptidase activity of penicillin-binding proteins (PBPs) at different stages of bacterial cell division. To facilitate the development of new fluorescent probes for PBP imaging, we evaluated 20 commercially available β-lactams for selective PBP inhibition in an unencapsulated derivative of the D39 strain of Streptococcus pneumoniae. Live cells were treated with β-lactam antibiotics at different concentrations and subsequently incubated with BOCILLIN FL (Boc-FL) to saturate uninhibited PBPs. Fluorophore-labeled PBPs were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and fluorescence scanning. Among 20 compounds tested, carbapenems (doripenem and meropenem) were co-selective for PBP1a, PBP2x, and PBP3, while six of the nine penicillin compounds were co-selective for PBP2x and PBP3. In contrast, the seven cephalosporin compounds tested display variability in their PBP-binding profiles. Three cephalosporin compounds cefoxitin, cephalexin and cefsulodin and the monobactam, aztreonam, exhibited selectivity for PBP3, while only cefuroxime (a cephalosporin) was selective for PBP2x. Treatment of S. pneumoniae cultures with a sublethal concentration of cefuroxime that inhibited 60% of PBP2x activity and less than 20% of the activity of other PBPs, resulted in formation of elongated cells. In contrast, treatment of S. pneumoniae cultures with concentrations of aztreonam and cefoxitin that inhibited up to 70% of PBP3 activity and less than 30% of other PBPs resulted in no discernible morphological changes. Additionally, correlation of the MIC and IC50 values for each PBP, with the exception of faropenem, mecillinam and 6-APA, suggests that pneumococcal growth inhibition is primarily due to the inhibition of PBP2x.

Copyright © 2015, American Society for Microbiology. All Rights Reserved.

PMID: 25845878

Commensal streptococci serve as a reservoir for beta-lactam resistance genes in Streptococcus pneumoniae.

Antimicrob Agents Chemother. 2015 Apr 6. pii: AAC.00429-15. [Epub ahead of print]

Commensal streptococci serve as a reservoir for beta-lactam resistance genes in Streptococcus pneumoniae.

Jensen A1, Valdórsson O2, Frimodt-Møller N3, Hollingshead S4, Kilian M2.

Author information

Abstract

Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, septicemia, and middle ear infections. The incidence of S. pneumoniae isolates non-susceptible to antibiotics has risen worldwide and may be above 20% in some countries. Beta-lactam antibiotic resistance in pneumococci is associated with significant sequence polymorphism in penicillin-binding proteins (PBPs). Commensal streptococci, especially S. mitis and S. oralis, have been identified as putative donors of mutated gene fragments. However, no studies have compared sequences of the involved pbp genes in large collections of commensal streptococci, with those of S. pneumoniae. We therefore investigated the sequence diversity at the nucleotide and amino acid levels of the transpeptidase region in 107, 96, and 88 strains of the three pbp genes, pbp2x, pbp2b, and pbp1a, respectively, of susceptible and non-susceptible strains of commensal streptococci to determine to what extent homologous recombination between commensal streptococci and S. pneumoniae play a role in the development of beta-lactam resistance in S. pneumoniae. In contrast to pneumococci, extensive sequence variation in the transpeptidase region of pbp2x, pbp2b, and pbp1a was observed in both susceptible and non-susceptible strains of commensal streptococci, conceivably reflecting the genetic diversity of the many evolutionary lineages of commensal streptococci combined with intra- and interspecies homologues recombination events. Our data support that resistance to beta-lactam antibiotics in pneumococci is due to sequences acquired from commensal Mitis group streptococci, especially S. mitis. However, several amino acid alterations previously linked to beta-lactam resistance in pneumococci appear to represent species signatures of the donor strain rather than being causal of resistance.

Copyright © 2015, American Society for Microbiology. All Rights Reserved.

PMID: 25845880 

Multiple mutations and increased RNA expression in tetracycline-resistant Streptococcus pneumoniae as determined by genome-wide DNA and mRNA sequencing.

J Antimicrob Chemother. 2015 Apr 9. pii: dkv060. [Epub ahead of print]

Multiple mutations and increased RNA expression in tetracycline-resistant Streptococcus pneumoniae as determined by genome-wide DNA and mRNA sequencing.

Lupien A1, Gingras H1, Bergeron MG1, Leprohon P1, Ouellette M2.

Author information

Abstract

OBJECTIVES:

The objective of this study was to characterize chromosomal mutations associated with resistance to tetracycline in Streptococcus pneumoniae.

METHODS:

Chronological appearance of mutations in two S. pneumoniae R6 mutants (R6M1TC-5 and R6M2TC-4) selected for resistance to tetracycline was determined by next-generation sequencing. A role for the mutations identified was confirmed by reconstructing resistance to tetracycline in a S. pneumoniae R6 WT background. RNA sequencing was performed on R6M1TC-5 and R6M2TC-4 and the relative expression of genes was reported according to R6. Differentially expressed genes were classified according to their ontology.

RESULTS:

WGS of R6M1TC-5 and R6M2TC-4 revealed mutations in the gene rpsJ coding for the ribosomal protein S10 and in the promoter region and coding sequences of the ABC genes patA and patB. These cells were cross-resistant to ciprofloxacin. Resistance reconstruction confirmed a role in resistance for the mutations in rpsJ and patA. Overexpression of the ABC transporter PatA/PatB or mutations in the coding sequence of patA contributed to resistance to tetracycline, ciprofloxacin and ethidium bromide, and was associated with a decreased accumulation of [3H]tetracycline. Comparative transcriptome profiling of the resistant mutants further revealed that, in addition to the overexpression of patA and patB, several genes of the thiamine biosynthesis and salvage pathway were increased in the two mutants, but also in clinical isolates resistant to tetracycline. This overexpression most likely contributes to the tetracycline resistance phenotype.

CONCLUSIONS:

The combination of genomic and transcriptomic analysis coupled to functional studies has allowed the discovery of novel tetracycline resistance mutations in S. pneumoniae.

© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

KEYWORDS:

ABC transporters; RNA-seq; S. pneumoniae; genomic; rpsJ; thiamine

PMID: 25862682