| 1. |
- Ahlstrand, Erik, 1974-, et al.
(författare)
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Long-term molecular epidemiology of staphylococcus epidermidis blood culture isolates from patients with hematological malignancies
- 2014
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Ingår i: PLOS ONE. - San Francisco, USA : Public Library Science. - 1932-6203. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis is an important cause of bloodstream infections in patients with hematological malignancies. Knowledge of the long-term epidemiology of these infections is limited. We surveyed all S. epidermidis blood culture isolates from patients treated for hematological malignancies at the University Hospital of Orebro, Sweden from 1980 to 2009. A total of 373 S. epidermidis isolates were identified and multilocus sequence typing, staphylococcal chromosome cassette mec (SCCmec) typing and standard antibiotic susceptibility testing were employed to characterize these isolates. The majority of the isolates 361/373 (97%) belonged to clonal complex 2, and the 373 isolates were divided into 45 sequence types (STs); Simpson's Diversity Index was 0.56. The most prevalent STs were ST2 (243/373, 65%) and ST215 (28/373, 8%). Ninety three percent (226/243) of the ST2 isolates displayed either SCCmec type III or IV. ST2 and 215 were isolated during the entire study period, and together these STs caused temporal peaks in the number of positive blood cultures of S. epidermidis. Methicillin resistance was detected in 213/273 (78%) of all isolates. In the two predominating STs, ST2 and ST215, methicillin resistance was detected in 256/271 isolates (95%), compared with 34/100 (34%) in other STs (p<0.001). In conclusion, in this long-term study of patients with hematological malignancies, we demonstrate a predominance of methicillin-resistant ST2 among S. epidermidis blood culture isolates.
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| 2. |
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| 3. |
- Bengtsson, Torbjörn, 1955-, et al.
(författare)
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Plantaricin NC8 αβ exerts potent antimicrobial activity against Staphylococcus spp. and enhances the effects of antibiotics
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The use of conventional antibiotics has substantial clinical efficacy, however these vital antimicrobial agents are becoming less effective due to the dramatic increase in antibiotic-resistant bacteria. Novel approaches to combat bacterial infections are urgently needed and bacteriocins represent a promising alternative. In this study, the activities of the two-peptide bacteriocin PLNC8 αβ were investigated against different Staphylococcus spp. The peptide sequences of PLNC8 α and β were modified, either through truncation or replacement of all L-amino acids with D-amino acids. Both L- and D-PLNC8 αβ caused rapid disruption of lipid membrane integrity and were effective against both susceptible and antibiotic resistant strains. The D-enantiomer was stable against proteolytic degradation by trypsin compared to the L-enantiomer. Of the truncated peptides, β1-22, β7-34 and β1-20 retained an inhibitory activity. The peptides diffused rapidly (2 min) through the bacterial cell wall and permeabilized the cell membrane, causing swelling with a disorganized peptidoglycan layer. Interestingly, sub-MIC concentrations of PLNC8 αβ substantially enhanced the effects of different antibiotics in an additive or synergistic manner. This study shows that PLNC8 αβ is active against Staphylococcus spp. and may be developed as adjuvant in combination therapy to potentiate the effects of antibiotics and reduce their overall use.
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| 4. |
- Ehlersson, Gustaf, et al.
(författare)
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Phenotypic characterisation of coagulase-negative staphylococci isolated from blood cultures in newborn infants, with a special focus on Staphylococcus capitis
- 2017
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Ingår i: Acta Paediatrica. - : John Wiley & Sons. - 0803-5253 .- 1651-2227. ; 106:10, s. 1576-1582
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Tidskriftsartikel (refereegranskat)abstract
- AIM: This Swedish study determined which species of coagulase-negative staphylococci (CoNS) were found in neonatal blood cultures and whether they included Staphylococcus capitis clones with decreased susceptibility to vancomycin.METHODS: CoNS isolates (n = 332) from neonatal blood cultures collected at Örebro University Hospital during 1987-2014 were identified to species level with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS). The antibiotic susceptibility pattern of S. capitis isolates was determined by the disc diffusion test and Etest, and the presence of heterogeneous glycopeptide-intermediate S. capitis (hGISC) was evaluated.RESULTS: Staphylococcus epidermidis (67.4%), Staphylococcus haemolyticus (10.5%) and S. capitis (9.6%) were the most common CoNS species. Of the S. capitis isolates, 75% were methicillin-resistant and 44% were multidrug-resistant. No isolate showed decreased susceptibility to vancomycin, but at least 59% displayed the hGISC phenotype. Staphylococcus capitis isolates related to the strain CR01 displaying pulsotype NRCS-A were found.CONCLUSION: Staphylococcus epidermidis, S. haemolyticus and S. capitis were the predominant species detected in neonatal blood cultures by MALDI-TOF MS. The number of episodes caused by S. capitis increased during the study period, but no isolates with decreased susceptibility to vancomycin were identified. However, S. capitis isolates related to the strain CR01 displaying pulsotype NRCS-A were found.
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| 5. |
- Golparian, Daniel, 1984-, et al.
(författare)
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Analytical specificity and sensitivity of the novel dual-target GeneProof Neisseria gonorrhoeae PCR kit for detection of N-gonorrhoeae
- 2015
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley-Blackwell. - 0903-4641 .- 1600-0463. ; 123:11, s. 955-958
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Tidskriftsartikel (refereegranskat)abstract
- Detection of Neisseria gonorrhoeae relies increasingly on nucleic acid amplification tests (NAATs). The specificity of many gonococcal NAATs has been suboptimal and supplementary testing remains recommended in Europe and several additional countries. The novel dual-target GeneProofNeisseria gonorrhoeae PCR kit, targeting porA pseudogene and 16S rRNA gene, showed a high specificity and sensitivity when isolates of non-gonococcal Neisseria and related species (n=144), and gonococci (n=104) were tested. However, rare gonococcal porA mutants were only detected in the 16S rRNA gene target and two non-gonococcal isolates showed a low-level cross-reactivity in the 16S rRNA gene target. The detection limit for both targets was 1.5 copies per reaction.
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| 6. |
- Hamad, Tarza, et al.
(författare)
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Antibiotic susceptibility among Staphylococcus epidermidis isolated from prosthetic joint infections, with focus on doxycycline
- 2015
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley-Blackwell. - 0903-4641 .- 1600-0463. ; 123:12, s. 1055-1060
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, coagulase-negative staphylococci such as Staphylococcus epidermidis have gained importance as nosocomial pathogens, especially in immunocompromised patients and prosthetic joint infections (PJIs). These infections are often long lasting and difficult to treat due to the production of bacterial biofilm and the transformation of the bacteria into a stationary growth phase. Rifampicin is able to penetrate the biofilm, but to reduce the risk of development of rifampicin resistance it should be used in combination with an additional antibiotic. In this study we used Etest to investigate the antimicrobial susceptibility of 134 clinical isolates of S.epidermidis obtained from PJIs to six oral antibiotics: doxycycline, rifampicin, linezolid, fusidic acid, clindamycin, and ciprofloxacin. We also performed synergy testing on doxycycline in combination with each of the remaining antibiotics. Ninety-three (69%) of the 134 isolates were susceptible to doxycycline, 94/134 (70%) to rifampicin, 56/134 (42%) to clindamycin, 25/134 (19%) to ciprofloxacin, 81/134 (60%) to fusidic acid, and 100% to linezolid. Thirty-two (80%) of the 40 isolates not fully susceptible to rifampicin were susceptible to doxycycline. Doxycycline in combination with each of the other investigated antibiotics exerted an additive effect on nearly half of the isolates, with the exception of clindamycin, which displayed an even higher percentage of additive effect (69%). To conclude, as the majority of the S.epidermidis isolates were susceptible to doxycycline, this antimicrobial agent may provide a potential alternative for combination therapy together with rifampicin.
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| 7. |
- Hedlund, Linda, et al.
(författare)
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Presence of arginine catabolic mobile element among community-acquired meticillin-resistant staphylococcus aureus is linked to a specific genetic background
- 2013
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - Malden, USA : Wiley-Blackwell. - 0903-4641 .- 1600-0463. ; 121:3, s. 221-225
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of arginine catabolic mobile element (ACME) among diverse and heterogeneous community-associated methicillin-resistant Staphylococcus aureus community-associated Methicillin-resistant S. aureus (CA-MRSA) (n = 114) in a low-endemic area, i.e. Sweden, was investigated. Among the CA-MRSA, represented by 47 different spa types, ACME was only found in 10 isolates with a common genetic background [t008, SCCmec type IV, Panton-Valentine leukocidin (PVL) positive, and indistinguishable or closely related pulsed-field gel electrophoresis (PFGE)-patterns] corresponding to USA300. This strain does not seem to be established in our area as most of the patients contracted the CA-MRSA abroad. Presence of ACME does not seem to be associated with colonization, long-term carriership, or intra-familiar transmission in a higher extent than CA-MRSA in general.
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| 8. |
- Hellmark, Bengt, 1971-, et al.
(författare)
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Comparison of Staphylococcus epidermidis isolated from prosthetic joint infections and commensal isolates in regard to antibiotic susceptibility, agr type, biofilm production, and epidemiology
- 2013
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Ingår i: International Journal of Medical Microbiology. - Jena, Germany : Elsevier. - 1438-4221 .- 1618-0607. ; 303:1, s. 32-39
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis is the predominant bacterial species in the normal flora of the human skin and superficial mucosal membranes. However, it has also emerged as the most important pathogen in infections related to foreign-body materials, such as prosthetic joints and heart valves. The aims of this study were to characterise S. epidermidis isolated from prosthetic joint infections (PJI; n = 61) and commensal isolates from healthy individuals (n = 24) in regard to antimicrobial sensitivity, agr type, hid gene presence, biofllm production including presence of ica and aap genes involved in the biofilm formation process and epidemiology using both phenotypic (the PhenePlate-system) and genotypic [multilocus sequence typing (MLST)] methods. Among the PJI isolates, the majority (67%) were multidrug-resistant. Two major clusters of PJI isolates could be identified; 44% belonged to MLST sequence type (ST) 2, all but one were of agr type 1, and 31% were assigned ST215 and were of agr type 3. Of the commensal isolates, only one isolate was multidrug-resistant, and they were more molecular epidemiologically diverse with mainly MLST singletons and a maximum of 3 isolates assigned to the identical ST. Biofilm production was detected in 41% of the PJI isolates and 58% of the commensal isolates, with the aap gene (95%) more frequently detected than the ica genes (62%) in the biofilm-positive isolates. In conclusion, S. epidermidis isolated from PJIs and commensal isolates differed regarding antimicrobial sensitivity and molecular epidemiological typing using MLST, but not substantially in the distribution of agr types, biofilm production, or the presence of ica and aap genes.
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| 9. |
- Hellmark, Bengt, 1971-
(författare)
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Genotypic and phenotypic characterisation of Staphylococcus epidermidis isolated from prosthetic joint infections
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Staphylococcus epidermidis has emerged in recent years as an important nosocomial pathogen, especially in infections associated with implanted foreign body materials (e.g., prosthetic joints and heart valves) and in individuals with a compromised immune system (e.g., cancer patients and neonates). Although rare, implant infections are long lasting and cause severe suffering for the patient that includes pain and disability and even increased mortality. One aim of the present thesis was to develop and evaluate a genetic method for species identification and simultaneous detection of rifampicin resistance in staphylococci. A second aim was to examine S. epidermidis isolated from prosthetic joint infections (PJIs) and from wrists and nares of healthy individuals regarding their antibiotic susceptibility, biofilm production, virulence factors, and epidemiology. Comparison with phenotypic diagnostics revealed that 8 (16%) of 49 isolates differed in their species identification in favour of the genetic method. In addition, mutations associated with rifampicin resistance, including two not previously reported, were possible to detect in all isolates resistant to rifampicin. Antibiotic susceptibility testing of 61 PJI isolates showed multi-drug resistance in 91%. Furthermore, the results of the synergy testing revealed that no antibiotic combination was significantly better than the others. Hence, the effects that were possible to detect were isolate dependent. To find a method for discriminating between invasive (n=61) and commensal (n=24) isolates of S. epidermidis genotypic and phenotypic characterisations of biofilm production (including the ica and aap genes), antibiotic susceptibility, virulence-related genes (such as agr and ACME) and epidemiology were performed (using multilocus sequence typing [MLST], typing of the staphylococcal chromosome cassette mec [SCCmec] and PhenePlate). Significant differences were found in antibiotic susceptibility, i.e. there was more resistance among invasive isolates. MLST sequence types (ST) ST2 and ST215 dominated the invasive isolates.
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| 10. |
- Hellmark, Bengt, 1971-, et al.
(författare)
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Staphylococcal cassette chromosome mec (SCCmec) and arginine catabolic mobile element (ACME) in Staphylococcus epidermidis isolated from prosthetic joint infections
- 2013
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - New York, USA : Springer. - 0934-9723 .- 1435-4373. ; 32:5, s. 691-697
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to characterise the staphylococcal cassette chromosome mec (SCCmec) in Staphylococcus epidermidis isolated from prosthetic joint infections (PJIs) and, if possible, assign them to any of the presently known SCCmec types. In addition, the isolates were examined for the presence of the arginine catabolic mobile element (ACME). Sixty-one S. epidermidis isolates obtained from PJIs and 24 commensal S. epidermidis isolates were analysed. The mecA gene was detected in 49 of the 61 (80 %) PJI isolates and in four of the 24 (17 %) commensal isolates, and the composition of the SCCmec was further analysed. SCCmec types I and IV were the most common types among the PJI isolates. However, for over half (57 %) of the isolates, it was not possible to assign an SCCmec type. ACME was detected in eight (13 %) of the PJI isolates and in 14 (58 %) of the commensal isolates. The characterisation of the SCCmec elements revealed a large heterogeneity, with a high frequency of isolates carrying more than one type of the ccr gene complex. ACME was more common among the commensal isolates and may represent a survival benefit for S. epidermidis colonising healthy individuals in the community.
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