Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii in Italy.

Conclusions: Our data reinforces the need to monitor the molecular epidemiology of CR A. baumannii and its associated antimicrobial resistance genes at national level. Background: Carbapenem-resistant (CR) Acinetobacter baumannii has been increasingly recognized as a major cause of health care-associated infections in critically ill patients and hospital outbreaks. Results: CR A. baumannii isolates assigned to international clonal lineage II (ICL II) and to ST78 clonal lineages were responsible for several epidemics in Italian hospitals during 2002-2018. Molecular analysis of carbapenem resistance showed the presence of OXA-58 CHDL in A. baumannii isolates assigned to ICL II and ST78 clonal lineage, which was replaced by OXA-23 CHDL in A. baumannii isolates assigned to ICL II since 2007 in several hospitals. CR A. baumannii was mainly responsible for respiratory tract infections and at a lesser extent for sepsis in intensive care unit patients. Methods: A narrative review of literature was conducted, searching PubMed database for articles on CR Acinetobacter spp. isolates from Italy published between January 2010 and December 2019.

Molecular epidemiology of a clonal outbreak of multidrug-resistant Acinetobacter baumannii in a university hospital in Italy.

This study investigated the molecular epidemiology of a clonal outbreak of multidrug-resistant Acinetobacter baumannii that occurred between June 2003 and June 2004 in a tertiary-care hospital in Naples, Italy. A. baumannii was isolated from 74 patients, of whom 38 were infected and 36 were colonised. Thirty-three patients had ventilator-associated pneumonia, three had hospital-acquired pneumonia, and two had sepsis. Genotypic analysis of 45 available A. baumannii isolates revealed two distinct pulsed-field gel electrophoresis (PFGE) patterns. Of these, PFGE pattern 1 was represented by isolates from 44 patients and was identical to that of an epidemic A. baumannii clone isolated in another hospital of Naples during 2002. All A. baumannii isolates of PFGE type 1 showed identical multiresistant antibiotypes, characterised by resistance to all antimicrobial agents tested, including carbapenems, with the exception of colistin. In these isolates, inhibition of OXA enzymes by 200 mM NaCl reduced the imipenem MIC by up to four-fold. Molecular analysis of antimicrobial resistance genes showed that all A. baumannii isolates of PFGE type 1 harboured a class 1 integron containing the aacA4, orfX and bla(OXA-20) gene cassettes, an ampC gene and a bla(OXA-51)-like allele. Moreover, a bla(OXA-58)-like gene surrounded by the regulatory elements ISAba2 and ISAba3 was identified in a 30-kb plasmid from A. baumannii isolates of PFGE type 1, but not PFGE type 2. Thus, selection of a single A. baumannii clone producing an OXA-58-type carbapenem-hydrolysing oxacillinase was responsible for the increase in the number of A. baumannii infections that occurred in this hospital.

Risk factors for extended-spectrum beta-lactamase-producing Serratia marcescens and Klebsiella pneumoniae acquisition in a neonatal intensive care unit.

We investigated the molecular epidemiology of gentamicin-resistant, extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Serratia marcescens, and risk factors associated with their acquisition in a neonatal intensive care unit (NICU) of a university hospital in Italy. During the study period (April-November 2004), S. marcescens was responsible for six infections and 31 colonisations, while K. pneumoniae was responsible for six infections and 103 colonisations. Concurrent isolation of both organisms occurred in 24 neonates. Molecular typing identified one major pulsed-field gel electrophoresis pattern each for S. marcescens and K. pneumoniae strains isolated during the study period. An 80 kb plasmid containing bla(SHV-12), bla(TEM-1) and aac(6')-Ib genes, isolated from both S. marcescens and K. pneumoniae strains, and showing identical restriction profiles, transferred resistance to third-generation cephalosporins to a previously susceptible Escherichia coli host. Birthweight, gestational age and use of invasive devices were significantly associated with S. marcescens and K. pneumoniae acquisition on univariate analysis, while empiric antimicrobial treatment with ampicillin and gentamicin, and duration of hospital stay, proved to be the only independent risk factors. In conclusion, conjugal plasmid transfer and empiric antimicrobial therapy with ampicillin and gentamicin might have contributed to the selection and spread of gentamicin-resistant ESBL-producing Enterobacteriaceae in the NICU.

Assessment of the efficacy of Umonium38 on multidrug-resistant nosocomial pathogens.

INTRODUCTION: We investigated the efficacy of a biocide Umonium38 on multidrug-resistant strains by comparison with a chloride derivative (Decs). METHODS: In vitro susceptibility tests were performed by agar diffusion disk and results were interpreted according to Clinical and Laboratory Standards Institute (CLSI). In vitro antibacterial efficacy of Umonium38 and Decs over selected strains was evaluated according to European Standards protocol with or without organic substance. RESULTS: In vitro tests with Umoniumnr at 2.5% concentration demonstrated an overall drop in microbial and yeast charges after 5 min. contact without organic substance. The same results were obtained in presence of organic substance. In vitro tests with chloride derivative at 5% without organic substance also resulted in overall drop in bacterial and mycotic charges. Conversely, in presence of organic substance, the hypochlorite reduced the initial 10 UFC/ml to 10 UFC/ml for all bacterial strains with a decrease of 4 log except for Enterococcus faecalis and Candida albicans whose reduction was 2 and 1 log units respectively. DISCUSSION: The organic substance in water requires large use of oxidising disinfectants (chloride, ozone) implying in the need for higher-than-standard concentrations. The disinfecting effect of chloride is only visible when the "requirement" of organic substance has been met. By contrast, Umonium38 behaves like a powerful biocide even in presence of organic substance, as it is not "consumed" by possible organic residues. CONCLUSIONS: Umonium38 resulted beneficial and effective. It is to be stressed, however, that all these experiments were in vitro tests and still requires validation from a correct use of clinical practice.

Molecular epidemiology of Stenotrophomonas maltophilia in a university hospital.

The aim of this investigation was to study the molecular epidemiology of Stenotrophomonas maltophilia in a university hospital in Italy. Sixty-one clinical isolates were collected from 43 patients during a two-year period. The majority of specimens were from the respiratory tract (41 of 43) of patients in the adult intensive care unit (ICU) (19 of 43) or cystic fibrosis (CF) patients (13 of 43). Genotypic analysis by pulsed-field gel electrophoresis (PFGE) of clinical isolates identified 31 different PFGE patterns. Although most patients were infected or colonized by different S. maltophilia clones, clones with identical genotype were isolated in patients from ICU, where two separate outbreaks were identified. Antimicrobial susceptibility identified a multi-resistant phenotype in all S. maltophilia PFGE clones. The majority of PFGE clones identified (six of seven clones from patients in the ICU) were susceptible to fluoroquinolones. Mechanical ventilation was associated with S. maltophilia acquisition in the ICU.

A nosocomial outbreak of Serratia marcescens producing inducible Amp C-type beta-lactamase enzyme and carrying antimicrobial resistance genes within a class 1 integron.

We investigated an outbreak of Serratia marcescens in the adult intensive care unit of the University Hospital of Napoli. The outbreak involved 13 cases of infection by S. marcescens over a nine-month period and was caused by a single pulsed-field gel electrophoresis clone. The epidemic strain was multiply antibiotic resistant, producing an inducible Amp C-type beta-lactamase enzyme and carrying the trimethoprim-resistance gene and the adenyltransferase gene, which confers resistance to streptomycin and spectinomycin, within a class 1 integron. Antimicrobial therapy with beta-lactams was associated with S. marcescens acquisition in the intensive care unit.

Clonal spread and patient risk factors for acquisition of extensively drug-resistant Acinetobacter baumannii in a neonatal intensive care unit in Italy.

AIM: To report an outbreak of extensively drug-resistant (XDR) Acinetobacter baumannii in the neonatal intensive care unit (NICU) of an Italian university hospital. Patient risk profiles for acquisition of A. baumannii and measures used to control the outbreak are described. METHODS: Antibiotic susceptibility of strains was evaluated by microdilution. Genotyping was performed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. Carbapenemase genes were analysed by polymerase chain reaction and DNA sequencing. A case-control study was designed to identify risk factors for acquisition of A. baumannii. FINDINGS: A. baumannii was isolated from 22 neonates, six of whom were infected. One major PFGE type was identified, assigned to sequence type (ST) 2, corresponding to International Clone II; this was indistinguishable from isolates from the adult ICU in the same hospital. A. baumannii isolates were resistant to aminoglycosides, quinolones and classes of ß-lactam antibiotics, but were susceptible to tigecycline and colistin. Carbapenem resistance was associated with the presence of transposon Tn2006 carrying the bla(OxA-23) gene. Length of NICU stay, length of exposure to A. baumannii, gestational age, use of invasive devices and length of exposure to invasive devices were significantly associated with acquisition of A. baumannii on univariate analysis, while length of exposure to central venous catheters and assisted ventilation were the only independent risk factors after multi-variate analysis. CONCLUSIONS: This XDR A. baumannii outbreak in an NICU was probably caused by intrahospital transfer of bacteria via a colonized neonate whose mother was admitted to the adult ICU. Strengthened infection control measures were necessary to control the outbreak.

High-dose intravenous corticosteroid therapy for Graves' ophthalmopathy.

In order to compare oral and high-dose iv corticosteroid therapy for Graves' disease, 25 patients with Graves' ophthalmopathy were treated with two weekly iv injections of 1 g of methylprednisolone diluted in 250-500 ml of physiological solution for 6 weeks, and were compared to a group of 26 patients treated with oral prednisone at a dose of 60-80 mg/day progressively reduced every 2 weeks for a total duration of 4-6 months. The efficacy of treatment was evaluated using the ophthalmopathy index score. Patients were followed at 3, 6, 12 months, and afterwards yearly. All patients showed a significant improvement in signs and symptoms of orbital inflammation and a slight improvement in proptosis and diplopia. Relevant side-effects were reported from patients receiving oral therapy, but no significant side-effects were observed in patients treated with high iv doses; a few cases presented with gastric pain (highly sensitive to aluminium oxide or ranitidine), while most of the patients referred to cutaneous rashes and a metal taste that disappeared some hours after the infusion. Improvements observed after treatment have been stable in both groups. In conclusion, in addition to a lower incidence of side-effects compared to the classic oral therapy, the high-dose iv steroid therapy provides efficient and stable improvement in Graves' ophthalmopathy.