Human Campylobacter spp. infections in Italy.

PURPOSE: Campylobacter is a frequent cause of enteric infections with common antimicrobial resistance issues. The most recent reports of campylobacteriosis in Italy include data from 2013 to 2016. We aimed to provide national epidemiological and microbiological data on human Campylobacter infections in Italy during the period 2017-2021. METHODS: Data was collected from 19 Hospitals in 13 Italian Regions. Bacterial identification was performed by mass spectrometry. Antibiograms were determined with Etest or Kirby-Bauer (EUCAST criteria). RESULTS: In total, 5419 isolations of Campylobacter spp. were performed. The most common species were C. jejuni (n = 4535, 83.7%), followed by C. coli (n = 732, 13.5%) and C. fetus (n = 34, 0.6%). The mean age of patients was 34.61 years and 57.1% were males. Outpatients accounted for 54% of the cases detected. Campylobacter were isolated from faeces in 97.3% of cases and in 2.7% from blood. C. fetus was mostly isolated from blood (88.2% of cases). We tested for antimicrobial susceptibility 4627 isolates (85.4%). Resistance to ciprofloxacin and tetracyclines was 75.5% and 54.8%, respectively; resistance to erythromycin was 4.8%; clarithromycin 2% and azithromycin 2%. 50% of C. jejuni and C. coli were resistant to ≥ 2 antibiotics. Over the study period, resistance to ciprofloxacin and tetracyclines significantly decreased (p < 0.005), while resistance to macrolides remained stable. CONCLUSION: Campylobacter resistance to fluoroquinolones and tetracyclines in Italy is decreasing but is still high, while macrolides retain good activity.

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options.

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

Antimicrobial Resistance of Genital Mycoplasma and Ureaplasma: A Multicentre Study Over a 5-Year Period in Italy (2017-2021).

Updated data on genital Mollicutes prevalence and antimicrobial susceptibility can help provide guidance for antibiotic stewardship and set up effective strategies for infection control policies. In this multicentre study, we assessed the prevalence and the resistance profile of Mycoplasma hominis (MH) and Ureaplasma species (U. parvum/U. urealyticum), analyzing data from 21,210 subjects who provided urogenital samples for Mollicutes detection by culture over a 5-year period (2017-2021) in two high-density urban areas in the North of Italy (i.e., Bologna and Lecco). Overall prevalence of Mollicutes infection was 22.3%, with women showing a significantly higher detection rate than men (p < 0.00001). The prevalence decreased with age (highest prevalence <30 years) and over the years considered. Ureaplasma strains were much more frequently detected (62.3%) compared to MH (8.3%) and to mixed infections (29.4%). Ureaplasma species showed high levels of ciprofloxacin resistance (39.5%), whereas MH strains were nonsusceptible to azithromycin and roxithromycin in about 60% of cases. Over time, a significant decrease of resistance to azithromycin and doxycycline was detected (p < 0.0001 and 0.0004, respectively), in parallel with an important increase of ciprofloxacin-resistance levels (p < 0.0001). Overall, our results revealed that minocycline and josamycin can be first-line drugs for Mollicutes empirical treatment.

Intravenous Fosfomycin for Systemic Multidrug-Resistant Pseudomonas aeruginosa Infections.

Human Pseudomonas infections have high morbidity and mortality rates. Pseudomonas bacteria can cause sepsis or septic shock; they produce biofilm and commonly exhibit a multidrug-resistant phenotype. The choice of antimicrobial therapy in many cases is challenging, and deep knowledge of clinical, microbiological, and pharmacological issues is required. Intravenous fosfomycin is being repurposed in a combination given its favorable pharmacokinetic/pharmacodynamic properties (a small molecule with favorable kinetic both in bloodstream infection and in deep-seated infections), antibiofilm activity, and its interesting synergistic effects with other antimicrobials. Recent literature on epidemiological, microbiological, pharmacological, and clinical data on intravenous fosfomycin therapy against Pseudomonas is herein reviewed and discussed.

Identification of IncA Plasmid, Harboring blaVIM-1 Gene, in S. enterica Goldcoast ST358 and C. freundii ST62 Isolated in a Hospitalized Patient.

In the present study, we analyzed the genome of two S. enterica strains TS1 and TS2 from stool and blood cultures, respectively, and one strain of C. freundii TS3, isolated from a single hospitalized patient with acute myeloid leukemia. The S. enterica Goldcoast ST358 (O:8 (C2-C3) serogroup), sequenced by the MiSeq Illumina system, showed the presence of ß-lactamase genes (blaVIM-1, blaSHV-12 and blaOXA-10), aadA1, ant(2″)-Ia, aac(6')-Iaa, aac(6')-Ib3, aac(6')-Ib-cr, qnrVC6, parC(T57S), and several incompatibility plasmids. A wide variety of insertion sequences (ISs) and transposon elements were identified. In C. freundii TS3, these were the blaVIM-1, blaCMY-150, and blaSHV-12, aadA1, aac(6')-Ib3, aac(6')-Ib-cr, mph(A), sul1, dfrA14, ARR-2, qnrVC6, and qnrB38. IncA plasmid isolated from E.coli/K12 transconjugant and C. freundii exhibited a sequence identity >99.9%. The transfer of IncA plasmid was evaluated by conjugation experiments.

New Antimicrobials for Gram-Positive Sustained Infections: A Comprehensive Guide for Clinicians.

Antibiotic resistance is a public health problem with increasingly alarming data being reported. Gram-positive bacteria are among the protagonists of severe nosocomial and community infections. The objective of this review is to conduct an extensive examination of emerging treatments for Gram-positive infections including ceftobiprole, ceftaroline, dalbavancin, oritavancin, omadacycline, tedizolid, and delafloxacin. From a methodological standpoint, a comprehensive analysis on clinical trials, molecular structure, mechanism of action, microbiological targeting, clinical use, pharmacokinetic/pharmacodynamic features, and potential for therapeutic drug monitoring will be addressed. Each antibiotic paragraph is divided into specialized microbiological, clinical, and pharmacological sections, including detailed and appropriate tables. A better understanding of the latest promising advances in the field of therapeutic options could lead to the development of a better approach in managing antimicrobial therapy for multidrug-resistant Gram-positive pathogens, which increasingly needs to be better stratified and targeted.

Endemic Systemic Mycoses in Italy: A Systematic Review of Literature and a Practical Update.

Endemic systemic mycoses such as blastomycosis, coccidioidomycosis, histoplasmosis, talaromycosis, paracoccidioidomycosis are emerging as an important cause of morbidity and mortality worldwide. We conducted a systematic review on endemic systemic mycoses reported in Italy from 1914 to nowadays. We found out: 105 cases of histoplasmosis, 15 of paracoccidioidomycosis, 10 of coccidioidomycosis, 10 of blastomycosis and 3 of talaromycosis. Most cases have been reported in returning travelers and expatriates or immigrants. Thirtytwo patients did not have a story of traveling to an endemic area. Fortysix subjects had HIV/AIDS. Immunosuppression was the major risk factor for getting these infections and for severe outcomes. We provided an overview on microbiological characteristics and clinical management principles of systemic endemic mycoses with a focus on the cases reported in Italy.

Candida lipolytica Bloodstream Infection in an Adult Patient with COVID-19 and Alcohol Use Disorder: A Unique Case and a Systematic Review of the Literature.

Candida lipolytica is an uncommon Candida species causing invasive fungemia. This yeast is mainly associated with the colonisation of intravascular catheters, complicated intra-abdominal infections, and infections in the paediatric population. Here, we report a case of C. lipolytica bloodstream infection in a 53-year-old man. He was admitted for an alcohol withdrawal syndrome and mild COVID-19. Among the primary risk factors for candidemia, only the use of broad-spectrum antimicrobials was reported. The empiric treatment was commenced with caspofungin and then targeted with intravenous fluconazole. Infective endocarditis was ruled out using echocardiography, and PET/TC was negative for other deep-seated foci of fungal infection. The patient was discharged after blood culture clearance and clinical healing. To the best of our knowledge, this is the first case of C. lipolytica candidemia in a patient with COVID-19 and alcohol use disorder. We performed a systematic review of bloodstream infections caused by C. lipolytica. Clinicians should be aware of the possibility of C. lipolytica bloodstream infections in patients with alcohol use disorder, especially in a COVID-19 setting.

Analysis of Antimicrobial Resistance Genes (ARGs) in Enterobacterales and A. baumannii Clinical Strains Colonizing a Single Italian Patient.

The dramatic increase in infections caused by critically multidrug-resistant bacteria is a global health concern. In this study, we characterized the antimicrobial resistance genes (ARGs) of K. pneumoniae, P. mirabilis, E. cloacae and A. baumannii isolated from both surgical wound and rectal swab of a single Italian patient. Bacterial identification was performed by MALDI-TOF MS and the antimicrobial susceptibility was carried out by Vitek 2 system. The characterization of ARGs was performed using next-generation sequencing (NGS) methodology (MiSeq Illumina apparatus). K. pneumoniae, P. mirabilis and E. cloacae were resistant to most ß-lactams and ß-lactam/ß-lactamases inhibitor combinations. A. baumannii strain was susceptible only to colistin. The presence of plasmids (IncN, IncR, IncFIB, ColRNAI and Col (MGD2)) was detected in all Enterobacterales but not in A. baumannii strain. The IncN plasmid and blaNDM-1 gene were found in K. pneumoniae, P. mirabilis and E. cloacae, suggesting a possible transfer of this gene among the three clinical species. Conjugation experiments were performed using K. pneumoniae (1 isolate), P. mirabilis (2 isolates) and E. cloacae (2 isolates) as donors and E. coli J53 as a recipient. The blaNDM-1 gene was identified by PCR analysis in all transconjugants obtained. The presence of four different bacterial species harboring resistance genes to different classes of antibiotics in a single patient substantially reduced the therapeutic options.

New polyimidazole ligands against subclass B1 metallo-ß-lactamases: Kinetic, microbiological, docking analysis.

Beta-lactam antibiotics are one of the most commonly used drug classes in managing bacterial infections. However, their use is threatened by the alarming phenomenon of antimicrobial resistance, which represents a worldwide health concern. Given the continuous spread of metallo-ß-lactamases (MBLs) producing pathogens, the need to discover broad-spectrum ß-lactamase inhibitors is increasingly growing. A series of zinc chelators have been synthesized and investigated for their ability to hamper the Zn-ion network of interactions in the active site of MBLs. We assessed the inhibitory activity of new polyimidazole ligands N,N'-bis((imidazol-4-yl)methyl)-ethylenediamine, N,N,N'-tris((imidazol-4-yl)methyl)-ethylenediamine, N,N,N,N'-tetra((imidazol-4-yl-methyl)-ethylenediamine toward three different subclasses B1 MBLs: VIM-1, NDM-1 and IMP-1 by in vitro assays. The activity of known zinc chelators such as 1,4,7,10,13-Pentaazacyclopentadecane, 1,4,8,11-Tetraazacyclotetradecane and 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid was also assessed. Moreover, a molecular docking study was carried to gain insight into the interaction mode of the most active ligands.

Deciphering variable resistance to novel carbapenem-based ß-lactamase inhibitor combinations in a multi-clonal outbreak caused by Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae resistant to ceftazidime/avibactam.

OBJECTIVES: Carbapenemase-producing Enterobacterales represent a major cause of difficult-to-treat infections world-wide. Novel ß-lactam/ß-lactamase inhibitor combinations, including ceftazidime/avibactam (CZA), meropenem/vaborbactam (MVB), and imipenem/relebactam (IMR), represented a break-through in the treatment of some carbapenemase-producing Enterobacterales infections. However, acquired resistance to these agents has been reported in Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales. Herein, we reported an outbreak caused by CZA-resistant, KPC-producing Klebsiella pneumoniae (KPC-Kp), which was also variably resistant to carbapenem-based ß-lactam/ß-lactamase inhibitor combinations. METHODS: Bacterial isolates were subjected to antimicrobial susceptibility testing, whole-genome sequencing, determination of blaKPC gene dosage, and analysis of carbapenemase activity. RESULTS: Overall, 15 KPC-Kp, nine CZA-resistant (CZAR), and six CZA-susceptible isolates were collected from an outbreak involving six patients in a neurorehabilitation facility. Of the nine CZAR isolates, seven were also resistant to MVB and one was also resistant to IMR. Whole-genome sequencing revealed that the outbreak was multi-clonal, with CZAR KPC-Kp belonging to the ST101, ST1519, and two ST512 sub-lineages, which were involved in two independent transmission clusters. Resistance to CZA was primarily mediated by overproduction of KPC-3 associated with increased gene dosage, a mechanism accounting for cross-resistance to MVB in most cases, and to IMR in a single KPC-Kp isolate; multiple OmpK36 aletarions were also detected. Mutated KPC (KPC-53) was detected in a single case. Positivity for CZAR KPC-Kp was inconstantly associated with previous CZA exposure. CONCLUSIONS: In this multi-clonal outbreak of KPC-Kp, the overproduction of KPC-3 was the leading mechanism of cross-resistance to CZA and MVB, whereas resistance to IMR appeared less affected. The emergence and dissemination of similar resistance mechanisms may have relevant clinical and diagnostic implications, and their surveillance is warranted.

Time to reconsider moxifloxacin anti-anaerobic activity?

Large data on moxifloxacin activity on anaerobes are old. Moxifloxacin is often used for empiric therapy therefore the knowledge of current epidemiologic data is fundamental. We analyzed 69 anaerobic strains, from a recent multicenter Italian study, for moxifloxacin susceptibility. Using EUCAST criteria 81% of Bacteroides spp. and 48% of anaerobes other than Bacteroides were resistant to moxifloxacin. Using CLSI criteria moxifloxacin resistance rates decrease to 35% for all anaerobes, and to 41% for Bacteroides spp. We reported an alarming increase in moxifloxacin resistance among anaerobes in Italy.

Acinetobacter baumannii Resistance to Sulbactam/Durlobactam: A Systematic Review.

Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) have limited therapeutic options. Sulbactam-durlobactam is a combination of two ßlactamase inhibitors with activity against CRAB under phase 3 clinical investigation. We performed a systematic review on in vitro studies reporting A. baumannii resistances against sulbactam/durlobactam. We considered "resistant" species to be those with MIC ≥ 8 mg/L. Ten studies were included in the review (9754 tested isolates). Overall, 2.3% of A. baumannii were resistant to sulbactam/durlobactam, and this percentage rose to 3.4% among CRAB subgroups and to 3.7% among colistin-resistant strains. Resistance was 100% among metallo ß-lactamase-producing strains. Overall, in 12.5% of cases, sulbactam/durlobactam resistance was associated with the production of NDM-1, in 31.7% of cases with the substitutions in the PBP3 determinants, and in the remaining cases the resistance mechanism was unknown. In conclusion, A. baumannii resistance towards sulbactam/durlobactam is limited, except for MBL-producing strains.

Molecular Characterization by Whole-Genome Sequencing of Clinical and Environmental Serratia marcescens Strains Isolated during an Outbreak in a Neonatal Intensive Care Unit (NICU).

The whole-genome sequencing (WGS) of eighteen S. marcescens clinical strains isolated from 18 newborns hospitalized in the Neonatal Intensive Care Unit (NICU) at Pescara Public Hospital, Italy, was compared with that of S. marcescens isolated from cradles surfaces in the same ward. The identical antibiotic resistance genes (ARGs) and virulence factors were found in both clinical and environmental S. marcescens strains. The aac(6')-Ic, tetA(41), blaSRT-3, adeFGH, rsmA, and PBP3 (D350N) genes were identified in all strains. The SRT-3 enzyme, which exhibited 10 amino acid substitutions with respect to SST-1, the constitutive AmpC ß-lactamase in S. marcescens, was partially purified and tested against some ß-lactams. It showed a good activity against cefazolin. Both clinical and environmental S. marcescens strains exhibited susceptibility to all antibiotics tested, with the exception of amoxicillin/clavulanate.

In Vitro Activity of Sulbactam-Durlobactam against Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates: A Multicentre Report from Italy.

In the present study, the in vitro activity of the sulbactam-durlobactam (SUL-DUR) combination was evaluated against 141 carbapenem-resistant A. baumannii (CRAb) clinical strains collected from six Italian laboratories. Over half (54.6%) of these isolates were resistant to colistin. The SUL-DUR combination was active against these CRAb isolates with MIC50 and MIC90 values of 0.5 mg/L and 4 mg/L, respectively. Only eleven isolates were resistant to SUL-DUR with MIC values ranging from 8 to 128 mg/L. The SUL-DUR resistant A. baumannii exhibited several antimicrobial resistance genes (ARGs) such as blaOXA-20, blaOXA-58, blaOXA-66, blaADC-25, aac(6')-Ib3 and aac(6')-Ib-cr and mutations in gyrA (S81L) and parC (V104I, D105E). However, in these isolates, mutations Q488K and Y528H were found in PBP3. Different determinants were also identified in these CRAb isolates, including adeABC, adeFGH, adeIJK, abeS, abaQ and abaR, which encode multidrug efflux pumps associated with resistance to multiple antibacterial agents. This is the first report on the antimicrobial activity of SUL-DUR against carbapenem-resistant A. baumannii isolates selected from multiple regions in Italy.

New Antimicrobial Options in the Clinical Practice of Infections Caused by Difficult-to-Treat Pathogens: A Global Opportunity for Public Health.

Antimicrobial resistance (AMR) is a serious cause of concern for public health [...].

A Two Amino Acid Duplication, L167E168, in the Ω-Loop Drastically Decreases Carbapenemase Activity of KPC-53, a Natural Class A ß-Lactamase.

KPC-53 enzyme is a natural KPC variant which showed a duplication of L167E168 residues in the Ω-loop structure. The blaKPC-53 gene was cloned both into pBC-SK and pET-24a vectors, and the recombinant plasmids were transferred by transformation in Escherichia coli competent cells to evaluate the antimicrobial susceptibility and to produce the enzyme. Compared to KPC-3, the KPC-53 was less stable and showed a dramatic reduction of kcat and kcat/Km versus several ß-lactams, in particular carbapenems. Indeed, a 2,000-fold reduction was observed in the kcat values of KPC-53 for imipenem and meropenem. Concerning inhibitors, KPC-53 was susceptible to tazobactam and clavulanic acid but maintained resistance to avibactam. The molecular modeling indicates that the L167E168 duplication in KPC-53 modifies the interactions between residues involved in the catalytic pocket, changing the flexibility of the Ω-loop, which is directly coupled with the catalytic properties of the KPC enzymes.

Anaerobic bloodstream infections in Italy (ITANAEROBY): A 5-year retrospective nationwide survey.

INTRODUCTION: A lack of updated data on the burden and profile of anaerobic bloodstream infections (ABIs) exists. We assessed the incidence of ABIs and trends in antimicrobial resistance in anaerobes isolated from blood in Italy. MATERIAL AND METHODS: We conducted a retrospective study on 17 Italian hospitals (2016-2020). Anaerobes isolated from blood culture and their in vitro susceptibility profiles (EUCAST-interpreted) were registered and analyzed. RESULTS: A total of 1960 ABIs were identified. The mean age of ABIs patients was 68.6 ± 18.5 years, 57.6% were males. The overall incidence rate of ABIs was 1.01 per 10.000 patient-days. Forty-seven% of ABIs occurred in medical wards, 17% in ICUs, 14% in surgical wards, 7% in hemato-oncology, 14% in outpatients. The three most common anti-anaerobic tested drugs were metronidazole (92%), clindamycin (89%) and amoxicillin/clavulanate (83%). The three most common isolated anaerobes were Bacteroides fragilis (n = 529), Cutibacterium acnes (n = 262) and Clostridium perfringens (n = 134). The lowest resistance rate (1.5%) was to carbapenems, whereas the highest rate (51%) was to penicillin. Clindamycin resistance was >20% for Bacteroides spp., Prevotella spp. and Clostridium spp. Metronidazole resistance was 9.2% after excluding C. acnes and Actinomyces spp. Bacteroides spp. showed an increased prevalence of clindamycin resistance through the study period: 19% in 2016, 33% in 2020 (p ≤ 0.001). CONCLUSIONS: Our data provide a comprehensive overview of the epidemiology of ABIs in Italy, filling a gap that has existed since 1995. Caution is needed when clindamycin is used as empirical anti-anaerobic drug.