Antonella Santona

Globally, antibiotic-resistant Klebsiella spp. cause healthcare-associated infections with high mortality rates, and the rise of hypervirulent Klebsiella pneumoniae (hvKp) poses a significant threat to human health linked to community-acquired infections and increasing non-susceptibility. We investigated the phenotypic and genetic features of 36 Klebsiella isolates recovered from invasive infections at Hospital Central of Maputo in Mozambique during one year. The majority of the isolates displayed multidrug resistance (MDR) (29/36) to cephalosporins, gentamicin, ciprofloxacin, and trimethoprim–sulfamethoxazole but retained susceptibility to amikacin, carbapenems, and colistin. Most isolates were ESBLs-producing (28/36), predominantly carrying the bla_CTX-M-15 and other beta-lactamase genes (bla_SHV, bla_TEM-1, and bla_OXA-1). Among the 16 genomes sequenced, multiple resistance genes from different antibiotic classes were identified, with bla_CTX-M-15, mostly in the ISEcp1-bla_CTX-M-15-orf477 genetic environment, co-existing with bla_TEM-1 and aac(3)-IIa in five isolates. Our results highlight the presence of polyclonal MDR ESBL-producing K. pneumoniae from eight sequence types (ST), mostly harbouring distinct yersiniabactin within the conjugative integrative element (ICE). Further, we identified susceptible hvKp ST23, O1-K1-type isolates carrying yersiniabactin (ybt1/ICEKp10), colibactin, salmochelin, aerobactin, and hypermucoid locus (rmpADC), associated with severe infections in humans. These findings are worrying and underline the importance of implementing surveillance strategies to avoid the risk of the emergence of the most threatening MDR hvKp.

Introduction: Candida spp. are responsible for infections ranging from local to systemic, and resistance to antifungal first-line therapy is increasing in non-albicans Candida species. We aimed to determine the etiology of candidiasis and the antifungal resistance of Candida spp. isolated in Hue hospitals, Central-Vietnam. Methods: Species identification was performed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry supported by fungal internal-transcribed-spacer amplification and sequencing. Antifungal susceptibility testing was performed by disk diffusion method and minimum inhibitory concentrations of azoles, caspofungin, and amphotericin B against C. tropicalis were determined by broth microdilution. Polymorphism of erg11 gene associated with fluconazole resistance was carried out by polymerase chain reaction and sequencing. Multilocus sequence typing (MLST) was used for typing selected C. albicans isolates. Results: Overall, 196 Candida isolates were detected, mostly C. albicans (48%), followed by C. tropicalis (16%), C. parapsilosis (11%), C. glabrata (9%), C. orthopsilosis (6%) and to a lesser extent another eight species. High rates of resistance to fluconazole and voriconazole (18.8%) were observed in C. tropicalis with five isolates co-resistant to both agents. Y132F and S154F missense mutations in the ERG11 protein were associated with fluconazole-resistance in C. tropicalis (67.7%). Resistance to caspofungin was found in one isolate of C. albicans. MLST identified a polyclonal population of C. albicans with multiple diploid sequence types, and with few lineages showing potential nosocomial spread. Conclusions: Resistance to triazole agents should be considered in C. tropicalis infections in the studied hospitals, and surveillance measures taken to avoid Candida diffusion.

Rare information is available on clinical Enterococcus faecium encountered in Sardinia, Italy. This study investigated the antimicrobial susceptibility profiles and genotypic characteristics of E. faecium isolated at the University Hospital of Sassari, Italy, using the Vitek2 system and PCR, MLST, or WGS. Vitek2 revealed two VanB-type vancomycin-resistant Enterococcus faecium (VREfm) isolates (MICs mg/L = 8 and ≥32) but failed to detect vancomycin resistance in one isolate (MIC mg/L ≤ 1) despite positive genotypic confirmation of vanB gene, which proved to be vancomycin resistant by additional phenotypic methods (MICs mg/L = 8). This vanB isolate was able to increase its vancomycin MIC after exposure to vancomycin, unlike the “classic” occult vanB-carrying E. faecium, becoming detectable by Vitek 2 (MICs mg/L ≥ 32). All three E. faecium had highly mutated vanB₂ operons, as part of a chromosomally integrated Tn1549 transposon, with common missense mutations in VanH and VanB₂ resistance proteins and specific missense mutations in the VanW accessory protein. There were additional missense mutations in VanS, VanH, and VanB proteins in the vanB₂-carrying VREfm isolates compared to Vitek2. The molecular typing revealed a polyclonal hospital-associated E. faecium population from Clade A1, and that vanB₂-VREfm, and nearly half of vancomycin-susceptible E. faecium (VSEfm) analyzed, belonged to ST117. Based on core genome-MLST, ST117 strains had different clonal types (CT), excluding nosocomial transmission of specific CT. Detecting vanB₂-carrying VREfm isolates by Vitek2 may be problematic, and alternative methods are needed to prevent therapeutic failure and spread.

The development of carbapenem resistance in extraintestinal pathogenic Escherichia coli (ExPEC) has significant clinical implications, particularly in countries where second-line antimicrobials are not readily available, rendering treatments ineffective, and ExPEC infections untreatable. Thus, early detection of high-risk ExPEC lineages and raising awareness of the specific mechanisms underlying carbapenem resistance are mandatory for the selection of appropriate treatment options and the prevention of E. coli spread. This study aims to investigate the phenotypic and genotypic features of the first NDM-5 carbapenemase-producing ExPEC strain isolated from the blood of a patient admitted to the Maputo Central Hospital (MCH), in Mozambique. E. coli SSM100 isolate was identified by MALDI-TOF, it displayed high-level resistance to third generation cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides, performing antimicrobial susceptibilities testing by VITEK 2 system. E. coli SSM100 isolate was classified through whole-genome sequencing as ST405-D-O102: H6, a globally distributed lineage associated with antimicrobial resistance, carrying the bla NDM-5 gene located on an F1:A1:B49 plasmid, coharboring bla CTX-M-15, bla TEM-1, aadA2 , sul1 , and dfrA12 genes. In addition, mutations in gyrA (S83L and D87N), parC (S80I and E84V), and parE (I529L) conferring fluoroquinolone resistance were also found. Moreover, SSM100 isolate carried 88 virulence genes, of which 28 are reported to be associated with UPEC. The emergence of NDM-5 carbapenemase in a pandemic ST405-D-O102:H6 clone in Mozambique is of great concern. Locations of extended-spectrum β-lactamase determinants and NDM-5 carbapenemase gene on Inc F -plasmid can increase their spread reinforcing the need for antimicrobial surveillance and the urgent introduction of carbapenemase detection tests in diagnostic laboratories of the country.

Introduction: Imported parasitosis, which do not require an invertebrate vector, are extremely dangerous and can lead to the occurrence of disease in currently parasite free areas. In the present study we report a case of multi-parasitic infection in a young immigrant from Ghana to Italy caused by filaria, Schistosoma sp. and Strongyloides sp. Case presentation: A 27-year-old Ghanaian man attended the Hospital of Nuoro (Sardinia), Italy, at the end of August 2015, claiming pain to the kidney and hypertensive crisis; the patient presented with dyspnea and epistaxis, chronic itchy skin of the back, shoulders, arms and legs, anuria and high creatinine, metabolic acidosis and hypereosinophilic syndrome. Serological test for parasitic infections were done, and showed a marked positivity for filaria, Schistosoma sp. and Strongyloides sp. The patient started the treatment immediately with two doses per day of Bassado Antibiotic (tetracycline) for twenty days and then with a single dose of 3 mg of ivermectin that was repeated after 3 months. Conclusions: Immigrant patients from endemic areas who show clinical signs, such as a general itching on the back, shoulders and arms and legs, should have a thorough history in order to make early diagnosis and prevent further complications. Therefore, general practitioners and doctors in Europe and in other parasitosis non-endemic countries, should consider to test for parasites in any immigrant from endemic countries to aid in establishing the final diagnosis and prevent further complications.

In this communication, a case of black grain eumycetoma produced by the fungus C. atrobrunneum is reported. The patient was initially misdiagnosed with M. mycetomatis eumycetoma based on the grains’ morphological and cytological features. However, further aerobic culture of the black grains generated a melanised fungus identified as C. atrobrunneum by conventional morphological methods and by internal transcribed spacer 2 (ITS2) ribosomal RNA gene sequencing. This is the first-ever report of C. atrobrunneum as a eumycetoma-causative organism of black grain eumycetoma. It is essential that the causative organism is identified to the species level, as this is important for proper patient management and to predict treatment outcome and prognosis.