In Vitro Activity of Cefiderocol Against Carbapenem-Resistant Enterobacterales and Pseudomonas aeruginosa

The objective of this study was to assess the susceptibility of cefiderocol against multidrug-resistant carbapenemase-producing and nonproducing bacteria. The panel comprised 182 isolates of the order Enterobacterales, and 40 strains of Pseudomonas aeruginosa. Antimicrobial susceptibility testing has been performed using broth microdilution method according to the European Committee on Antimicrobial Susceptibility Testing recommendations. Mass spectrometry matrix-assisted laser desorption/ionization-time of flight mass spectrometry and carbapenemase-producing test were used to verify the presence of carbapenemases in clinical isolates. The genetic expression of single carbapenemases (blaKPC, blaOXA-48, blaNDM, blaVIM, blaIMP, blaGES) was determined by real-time polymerase chain reaction. Cefiderocol exhibited a good activity against the majority of strains tested in this study. Altogether, growth of 81.9% (n = 149) strains of the order Enterobacterales and 77.5% (n = 31) of P. aeruginosa isolates were inhibited at minimal inhibitory concentration (MIC) ≤2 mg/L. Values MIC50/MIC90 were 0.5/8 mg/L for enterobacteria, and 1/8 mg/L for P. aeruginosa. One isolate (Klebsiella pneumoniae) harboring two carbapenemases (blaOXA-48, blaNDM) had cefiderocol MIC 0.5 mg/L. In enterobacteria resistant to cefiderocol, blaNDM carbapenemase prevailed (43.3%, n = 29), followed by blaOXA-48 (31.3%, n = 21) and blaKPC (4.5%, n = 3). blaIMP (n = 8) and blaVIM (n = 1) metallo-β-lactamases dominated in cefiderocol-resistant P. aeruginosa (n = 9) isolates. Very good susceptibility (100%) to this drug showed blaGES-positive strains of P. aeruginosa (n = 8) and isolates resistant to meropenem without confirmed carbapenemase gene (n = 10). In this study, cefiderocol demonstrated potent activity against important nosocomial pathogens, therefore, therapeutic options of this drug against multidrug-resistant bacteria should be considered.

Characterization of Haemophilus influenzae Strains with Non-Enzymatic Resistance to β-Lactam Antibiotics Caused by Mutations in the PBP3 Gene in the Czech Republic in 2010-2018

The surveillance data on antibiotic resistance of Haemophilus influenzae have shown that strains with non-enzymatic resistance to β-lactam antibiotics have been on the rise in the Czech Republic over the last decade. This type of resistance is more difficult to detect than β-lactamase production. Analysis of 228 H. influenzae strains revealed that isolates with non-enzymatic resistance to β-lactams due to mutations in the ftsI gene could be reliably demonstrated by single run testing of susceptibility to amoxicillin/clavulanic acid (sensitivity of detection is 84.6%), cefuroxime (92.6%), ampicillin and penicillin (both 95.7%). Thirty-seven different amino acid substitution combinations were detected in the PBP3 protein at 23 positions (V329I, D350N, S357N, A368T, M377I, S385T, A388V, L389F, P393L, A437S, I449V, G490E, I491V, R501L, A502S, A502T, A502V, V511A, R517H, I519L, N526K, A530S, and T532S). The most common combination (35%) of amino acid substitutions was the combination D350N, M377I, A502V, N526K. Epidemiological typing does not indicate a clonal spread of a particular MLST type. Altogether there has been detected 74 STs. The most prevalent ST 1034 was associated mainly with a combination D350N, M377I, A502V, N526K. Clonal analysis revealed six clonal complexes (CCs) with the founder found, eight CCs without founder and 33 singletons.

Antibiotic Resistance, spa Typing and Clonal Analysis of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Blood of Patients Hospitalized in the Czech Republic

Staphylococcus aureus is one of the major causes of bloodstream infections. The aim of our study was to characterize methicillin-resistant Staphylococcus aureus (MRSA) isolates from blood of patients hospitalized in the Czech Republic between 2016 and 2018. All MRSA strains were tested for antibiotic susceptibility, analyzed by spa typing and clustered using a Based Upon Repeat Pattern (BURP) algorithm. The representative isolates of the four most common spa types and representative isolates of all spa clonal complexes were further typed by multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. The majority of MRSA strains were resistant to ciprofloxacin (94%), erythromycin (95.5%) and clindamycin (95.6%). Among the 618 strains analyzed, 52 different spa types were detected. BURP analysis divided them into six different clusters. The most common spa types were t003, t586, t014 and t002, all belonging to the CC5 (clonal complex). CC5 was the most abundant MLST CC of our study, comprising of 91.7% (n = 565) of spa-typeable isolates. Other CCs present in our study were CC398, CC22, CC8, CC45 and CC97. To our knowledge, this is the biggest nationwide study aimed at typing MRSA blood isolates from the Czech Republic.

Whole genome sequencing of macrolide resistant Streptococcus pneumoniae serotype 19A sequence type 416

Background

The resistance of Streptococcus pneumoniae to macrolides is becoming an increasingly important issue and thus it is important to understand the genetics related to adaptation of this species to the widespread use of antibiotics in Europe. The 58 isolates of S. pneumoniae belonging to sequence type (ST) 416 and serotype 19A and to several different phenotypes originated from Italy, Portugal and Czech Republic were thus sequenced on Illumina MiSeq. The aim of the study was to describe genetical origine of isolates, investigate their macrolide resistance and suggest reasons for spread of ST416 in the Czech Republic.

Results

Investigation of genes associated with serotype determined serotype switch between 15B and 19A serotypes and core genome multilocus sequence typing (cgMLST) confirmed the origine of concerned isolates in Netherlands^15B-37 clone. Inspected genomes proved variability of genes associated with the macrolide resistance even within closely genetically relative isolates.

Conclusions

Participation of 19A/ST416 on the spread of Netherlands^15B-37 is accompanied by serotype switch between 19A and 15B serotypes and with acquisition of genes involved in macrolide resistance to the clone that was originally macrolide susceptible. There is evident tendency to interchanging and modifications of these and surrounding genes, that could lead to accelerate spreading of this sequence type in regions with high macrolide consumption.

Isolation of Bordetella trematum from the respiratory tract of a patient with lung cancer: a case report

We report the case of isolation of Bordetella trematum from the respiratory tract of a patient with lung carcinoma. This gram-negative, opportunistic rod was firstly described in 1996. To date, only several strains of Bordetella trematum have been isolated and reported, mostly from skin and soft tissue infections. The patient was admitted to the ICU of the Pulmonary Department in incipient septic shock with respiratory failure. Intravenous fluid resuscitation and non-invasive ventilation were administered immediately. A broad spectrum antibiotic piperacillin/tazobactam was administered empirically after sampling of material for microbiological examination. The bronchoscopy showed a large cavern of decayed tumour invading into mediastinum. Both sample cultures showed significant quantities of gram-negative non-fermenting bacteria. The isolate was identified using MALDI-TOF MS as Bordetella trematum and the identification was confirmed using 16S ribosomal RNA sequencing. In the last few years, routine bacterial identification using MALDI-TOF MS has enabled correct discrimination of this species. Nevertheless, isolation of Bordetella trematum in clinical samples is still very uncommon, and it is appropriate to confirm the species identification via 16S ribosomal RNA sequencing. To our knowledge, this is the first case of B. trematum isolated from the human respiratory tract since its first description. The clinical significance of Bordetella trematum in the rapid deterioration of the patient's status remains unclear.

The association of pili with the emergence and replacement of the major antibiotic resistant pneumococcal clones

BACKGROUND

The aim of this study was to evaluate the presence of pilus islet 1 (PI-1) and to determine its clade type in pneumococcal isolates with reduced susceptibility to penicillin (penicillin non-susceptible pneumococci - PNSP) and/or resistant to macrolides isolated prior to and after the introduction of pneumococcal conjugate vaccines (PCVs) in the Czech Republic.

METHODS

Clinical isolates of serotypes 9V (n = 68) and 19A (n = 89) were examined. Isolates were characterised by multilocus sequence typing (MLST). The presence of PI-1 was determined by screening for the sortase B, C, and D genes located within PI-1. In the presence of PI-1 pilus, clade types were classified by PCR.

RESULTS

In the pre-PCV period (2000-2007), the prevalence of PNSP was 3.9% and 2.7% of isolates were resistant to erythromycin. During 2012-2015 (post-PCV period), the rates of PNSP remained stable (3.6%), but resistance to erythromycin increased to 8.3%. While in 2000-2007, resistance to antibiotics was associated mainly with serotype 9V, in 2012-2015, it was replaced by serotype 19A. PI-1 positive isolates were seen in both serotypes. All isolates (68) of serotype 9V belonged to the Spain^9V-3 (CC156) clone and carried PI-1 of clade type I while 96.5% (56/58) of isolates of 19A serotype belonged to the Netherlands^15B-37 (CC199) clone and carried PI-1 of clade type II.

CONCLUSIONS

Both major antibiotic resistant clones carried PI-1, although they differ in the clade type. Thus the role of PI-1 should be evaluated in further studies and potentially considered in the spread of antibiotic resistant clones.

[Role of androgens in externalizing behavior problems in adolescents]

OBJECTIVE

While an association between androgens and different types of aggression has been well documented in male offenders, the influence of androgens on externalizing behavior in adolescents at risk for antisocial behavior has not been investigated so far.

METHODS

Plasma levels of the main androgen metabolites testosterone (T) and 5a-dihydrotestosterone (DHT) were measured in N = 119 14-year-olds (51 boys, 68 girls) from a prospective longitudinal study of children at risk. The Achenbach Child Behavior Checklist (CBCL) and the Youth Self Report Form (YSR) were used to assess externalizing behavior at age 14.

RESULTS

The CBCL revealed significant positive correlations between DHT levels and the subscales "externalizing problems" and the problem scales "aggressive behavior" and "delinquent behavior" in male adolescents. Only the YSR subscale "delinquent behavior" exhibited a marginally significant association with DHT. Neither scale showed any significant correlations between androgen levels and externalizing behavior in female adolescents.

CONCLUSIONS

Earlier findings of androgen effects on aggressive and antisocial behavior in male offenders were confirmed for male adolescents from a general population sample. The results stress the importance of the androgen metabolite DHT.