Emergence of Clonally-Related South Asian Clade I Clinical Isolates of Candida auris in a Greek COVID-19 Intensive Care Unit.

Candida auris has recently emerged as a multidrug-resistant yeast implicated in various healthcare-associated invasive infections and hospital outbreaks. In the current study, we report the first five intensive care unit (ICU) cases affected by C. auris isolates in Greece, during October 2020-January 2022. The ICU of the hospital was converted to a COVID-19 unit on 25 February 2021, during the third wave of COVID-19 in Greece. Identification of the isolates was confirmed by Matrix Assisted Laser Desorption Ionization Time of Flight mass spectroscopy (MALDI-TOF]. Antifungal susceptibility testing was performed by the EUCAST broth microdilution method. Based on the tentative CDC MIC breakpoints, all five C. auris isolates were resistant to fluconazole (≥32 µg/mL), while three of them exhibited resistance to amphotericin B (≥2 µg/mL). The environmental screening also revealed the dissemination of C. auris in the ICU. Molecular characterization of C. auris clinical and environmental isolates was performed by MultiLocus Sequence Typing (MLST) of a set of four genetic loci, namely ITS, D1/D2, RPB1 and RPB2, encoding for the internal transcribed spacer region (ITS) of the ribosomal subunit, the large ribosomal subunit region and the RNA polymerase II largest subunit, respectively. MLST analysis showed that all isolates possessed identical sequences in the four genetic loci and clustered with the South Asian clade I strains. Additionally, PCR amplification and sequencing of the CJJ09_001802 genetic locus, encoding for the "nucleolar protein 58" that contains clade-specific repeats was performed. Sanger sequence analysis of the TCCTTCTTC repeats within CJJ09_001802 locus also assigned the C. auris isolates to the South Asian clade I. Our study confirms that C. auris is an emerging yeast pathogen in our region, especially in the setting of the ongoing COVID-19 worldwide pandemic. Adherence to strict infection control is needed to restrain further spread of the pathogen.

Possible COVID-19-Associated Pulmonary Aspergillosis Due to Aspergillus niger in Greece.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes direct damage to the pulmonary epithelium, enabling Aspergillus invasion. Rapid progression and high mortality of invasive aspergillosis have been reported. In the present study, we report a rare case of possible COVID-19-associated pulmonary aspergillosis (CAPA) caused by A. niger in a Greek patient. Diagnosis was based on ECMM/ISHAM specific criteria and the new algorithm "BM-AspICU" for the invasive pulmonary aspergillosis diagnostic strategy. The fungal isolate was recovered in a non-bronchoalveolar lavage (non-BAL) sample and its identification was performed by standard macroscopic and microscopic morphological studies. MALDI-TOF analysis confirmed the identification of A. niger. In addition, galactomannan antigen and Aspergillus real-time PCR testing were positive in the non-BAL sample, while in serum they proved negative. The A. niger isolate showed an MIC for fluconazole ≥128 µg/mL, for itraconazole and posaconazole 0.25 µg/mL, for voriconazole 0.5 µg/mL, for flucytosine 4 µg/mL, for amphotericin B 1 µg/mL, and for all echinocandins (caspofungin, anidulafungin, micafungin) >8 µg/mL. The patient was initially treated with voriconazole; amphotericin B was subsequently added, when a significant progression of cavitation was demonstrated on chest computed tomography. A. niger was not isolated in subsequent samples and the patient's unfavorable outcome was attributed to septic shock caused by a pandrug-resistant Acinetobacter baumannii strain.

Changing Characteristics and In Vitro Susceptibility to Ceftazidime/Avibactam of Bloodstream Extensively Drug-Resistant Klebsiella pneumoniae from a Greek Intensive Care Unit.

During 2014-2016, a total of 248 carbapenem-resistant Klebsiella pneumoniae (CARB-R Kp) were recovered in a Greek intensive care unit (ICU), the colistin resistance (COL-R) rates among CARB-R Kp from bloodstream infections (BSIs) were determined, and molecular characterization and the in vitro susceptibility of CARB-R+COL-R Kp to ceftazidime/avibactam were performed. The majority of CARB-R Kp from BSIs (n = 53) were OXA-48 (43.4%) and KPC (33.9%) producers, but no statistically significant differences were observed for the clinical characteristics of ICU patients affected by OXA-48 and other carbapenemase-producing K. pneumoniae. CARB-R+COL-R Kp (n = 28) represented 52.8% of 53 CARB-R Kp recovered from BSIs. The increase in the COL-R rates from 2014 to 2015 was mainly associated with the diffusion of extensively drug-resistant (XDR) OXA-48-co-producing CTX-M-15-like K. pneumoniae, assigned to multilocus-sequence typing ST101, possessing alterations in the mgrB loci. Ceftazidime/avibactam was active against all OXA-48 and KPC producers. Thus, the spread of XDR Kp possessing different types of carbapenemases further complicates the infection control strategies for the management of XDR Kp, whereas ceftazidime/avibactam may be a reasonable alternative to colistin for the treatment of XDR Kp in settings with low prevalence of metallo-ß lactamase-producing K. pneumoniae.

Investigation of Extensively Drug-Resistant blaOXA-23-Producing Acinetobacter baumannii Spread in a Greek Hospital.

A rapid increase was observed in the incidence of extensively drug-resistant Acinetobacter baumannii (XDR Aba) isolates in a Greek hospital during 2014. To investigate the causes of this rise, the antimicrobial resistance profiles of all carbapenem-resistant (CARB-R) Aba isolates recovered during 2014-2015 were determined. Selected XDR Aba isolates (n = 13) were characterized by molecular methods. XDR Aba (48 isolates) represented 21.4% of the 224 CARB-R Aba recovered during the study period. The 13 selected XDR Aba isolates were positive for the blaOXA-23, the intrinsic blaOXA-51, and the adeB gene of the AdeABC efflux pump, and all belonged to the 3LST ST101, corresponding to the international clone II. Three bloodstream isolates possessed two amino acid substitutions (A138T+A226V) in the deduced amino acid sequences of the pmrB gene, which may be implicated in colistin resistance. This study demonstrates that this clone still evolves by obtaining an ever-increasing arsenal of antibiotic resistance mechanisms. The clinical characteristics of the intensive care unit (ICU) patients with XDR Aba were reviewed retrospectively. Infected ICU patients with XDR Aba displayed higher death rates compared with infected ICU patients susceptible to colistin and tigecycline CARB-R Aba, although there were no statistically significant differences. Conclusively, continuous surveillance and molecular characterization of XDR Aba, combined with strict infection control measures are mandatory for combating nosocomial infections caused by this organism.

Characterization of ST258 Colistin-Resistant, blaKPC-Producing Klebsiella pneumoniae in a Greek Hospital.

The emergence of colistin resistance may further contribute to treatment failure of infection caused by multidrug-resistant (MDR) Klebsiella pneumoniae. The colistin resistance rates were determined and colistin-resistant carbapenemase-producing K. pneumoniae (COL-R CP-Kp) were characterized over an 18-month period in a Greek hospital. Out of 135 carbapenemase producers, 19 isolates (14%) were categorized as resistant to colistin. Phenotypic and molecular characterization of the COL-R CP-Kp isolates revealed that all were MDR blaKPC producers and, excluding one isolate of MLST ST383, belonged to the international clonal lineage ST258. Furthermore, PCR amplification and sequencing of the mgrB locus revealed nucleotide sequences of different sizes and insertions of IS1- and IS5-like mobile elements. The majority (63%) of the COL-R blaKPC producers was recovered from patients in the intensive care unit (ICU) and clinical data indicated that all patients should have acquired these isolates in the ICU. The findings of the present study underscore a concerning evolution of colistin resistance in a setting of high K. pneumoniae carbapenemase (KPC)-Kp endemicity, such as Greece. Thus, continuous surveillance, molecular characterization, prudent use of antibiotics, and implementation of infection control measures for K. pneumoniae are urgent.

Molecular identification of tigecycline- and colistin-resistant carbapenemase-producing Acinetobacter baumannii from a Greek hospital from 2011 to 2013.

An alarming increase in the resistance rates of tigecycline and colistin among carbapenemase-producing Acinetobacter baumannii recovered from a Greek hospital over a 3-year period (2011-2013) was investigated. The antimicrobial resistance profiles and carbapenemase gene content were determined for a collection of colistin- and/or tigecycline-resistant carbapenemase-producing A. baumannii isolates (n = 42), which were recovered consecutively during the study period. A gradual increase in the incidence of blaOXA-23 producers was observed from 2011 to 2013. A cluster of 21 isolates comprised tigecycline-resistant blaOXA-23 producers displayed a single antimicrobial resistance pattern. The emergence of two blaOXA-23 producers resistant to both tigecycline and colistin was documented. Furthermore, determination of the mechanisms of colistin and tigecycline resistance and molecular typing by the tri-locus sequence typing (3LST) scheme for nine isolates recovered from bloodstream infections were performed. Out of nine isolates, five tigecycline- and two colistin-resistant isolates were blaOXA-23 producers of 3LST ST101 corresponding to the international clone II recovered during 2012-2013. All nine isolates were positive for the presence of the adeB gene of the AdeABC efflux pump. Three colistin-resistant isolates possessed novel substitutions in PmrB, which may be implicated in colistin resistance. To the best of our knowledge, this is the first report of the acquisition of tigecycline and colistin resistance among blaOXA-23-producing A. baumannii of 3LST ST101 in Greece; thus, continuous surveillance and molecular characterization, prudent use of antibiotics and implementation of infection control measures for A. baumannii are urgent.