Molecular Epidemiology of Multidrug-Resistant
            <i>Acinetobacter baumannii</i>
            in a Tertiary Care Hospital in Naples, Italy, Shows the Emergence of a Novel Epidemic Clone

Giannouli, Maria; Cuccurullo, Susanna; Crivaro, Valeria; Popolo, Anna Di; Bernardo, Mariano; Tomasone, Federica; Amato, Gerardino; Brisse, Sylvain; Triassi, Maria; Utili, Riccardo; Zarrilli, Raffaele

doi:10.1128/jcm.02263-09

Cited by 79 publications

(73 citation statements)

References 26 publications

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“…ST-2 corresponds to international clone II. It has been described as being the most common ST in Mediterranean countries (7,11,15) and was the most prevalent ST in the present study (47.5%). ST-2 was shared by all clones of cluster D (clones D1 to D7), which were widely distributed across the Spanish provinces examined during the period of 1997 to 2007, accounting for more than 50% of isolates (Fig.…”

Section: Discussionmentioning

confidence: 73%

“…Many hospitals have included this kind of analysis among the measures taken to eradicate outbreaks (8,15,26,29). This work shows that typing studies provide information about time-clonal distribution in different hospital wards and the clonal complexity of outbreaks.…”

Section: Discussionmentioning

confidence: 99%

“…ST-3 (5.1%) corresponds to international clone III and appeared in cluster G (clones G1 to G3). The cluster G clones, although minority clones, had a sporadic time distribution throughout the study period ( (10,11,15,27,38). The imipenem-susceptible isolates showed no homogeneous distribution; rather, they showed a biased distribution in cluster A (ST-79), clone C (ST-81), and clones D3, D4, and D7 (all of them of ST-2) (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…PFGE offers exhaustive information for outbreak studies, which is useful in local settings and even in nationwide comparisons (28). MLST is a portable typing method (21) that allows interlaboratory comparisons and the large-scale monitoring of the growing list of national and international epidemic clones involved in nosocomial outbreaks (9,10,11,15,28,38).…”

Section: Discussionmentioning

confidence: 99%

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Clonal Diversity of Nosocomial Epidemic Acinetobacter baumannii Strains Isolated in Spain

et al. 2011

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Acinetobacter baumannii is one of the major pathogens involved in nosocomial outbreaks. The clonal diversity of 729 epidemic strains isolated from 19 Spanish hospitals (mainly from intensive care units) was analyzed over an 11-year period. Pulsed-field gel electrophoresis (PFGE) identified 58 PFGE types that were subjected to susceptibility testing, rpoB gene sequencing, and multilocus sequence typing (MLST). All PFGE types were multidrug resistant; colistin was the only agent to which all pathogens were susceptible. The 58 PFGE types were grouped into 16 clones based on their genetic similarity (cutoff of 80%). These clones were distributed into one major cluster (cluster D), three medium clusters (clusters A, B, and C), and three minor clusters (clusters E, F, and G). Multidrug-resistant Acinetobacter baumannii is a bacterium frequently endemic in certain hospital wards and is responsible for numerous nosocomial outbreaks around the world (3,23,33). Its great capacity to survive in low-moisture environments and its ability to develop resistance to antimicrobial agents afford A. baumannii the possibility of spreading in hospitals. The skin, oropharynx, and digestive tract are the main body areas colonized in hospitalized patients. The risk of colonization and subsequent infection are associated with factors such as the presence of underlying severe illnesses, long-term hospitalization, stays in specific hospital wards, selective antimicrobial pressure, and invasive interventions such as the use of mechanical ventilation or catheters (4,12,14,18).Nosocomial outbreaks of A. baumannii can have their origin in a single reservoir or in multiple contaminated sites (37, 39), and infection can have serious repercussions for patient morbidity and mortality. Patients can acquire the bacterium from an environmental source or from other patients (6, 18).The clonal study of hospital strains is very important in terms of an understanding of the epidemiology of these outbreaks. The aim of the present work was therefore to analyze the genetic diversity and clonal distribution of epidemic strains of A. baumannii isolated from around Spain over a long period of time. Isolates collected during outbreaks at different hospitals were analyzed by pulsed-field gel electrophoresis (PFGE), sequencing of the RNA polymerase ␤ subunit (rpoB) gene, and multilocus sequence typing (MLST). The results were then compared. Antimicrobial susceptibility testing was also performed to determine the multidrug resistance phenotypes of these epidemic strains. MATERIALS AND METHODSBacterial strains. Over the 11-year period from 1997 to 2007, an initial 814 A. baumannii strains isolated from clinical settings and suspected of being involved in nosocomial outbreaks were sent to the Spanish National Center for Microbiology (CNM) for typing. Strains were isolated from 19 public hospitals in 17 Spanish provinces. Hospitals were coded H1 to H19, and provinces were coded P1 to P17. The type of clinical sample, the hospital ward of origin, and the isolation per...

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Clonal Diversity of Nosocomial Epidemic Acinetobacter baumannii Strains Isolated in Spain

et al. 2011

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“…Three isolates obtained from centers located in Naples, Catania, and Genoa (the Genoan isolate was from an outpatient) be- longed to a previously described national clonal lineage (27). MLST and SG analyses revealed that these isolates belong to ST78 and SG6.…”

Section: Proportions Of Crab Isolates From Inpatients and Outpatientsmentioning

confidence: 99%

Epidemic Diffusion of OXA-23-Producing Acinetobacter baumannii Isolates in Italy: Results of the First Cross-Sectional Countrywide Survey

et al. 2014

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e Carbapenem-resistant Acinetobacter baumannii (CRAb) is emerging worldwide as a public health problem in various settings. The aim of this study was to investigate the prevalence of CRAb isolates in Italy and to characterize their resistance mechanisms and genetic relatedness. A countrywide cross-sectional survey was carried out at 25 centers in mid-2011. CRAb isolates were reported from all participating centers, with overall proportions of 45.7% and 22.2% among consecutive nonreplicate clinical isolates of A. baumannii from inpatients (n ‫؍‬ 508) and outpatients (n ‫؍‬ 63), respectively. Most of them were resistant to multiple antibiotics, whereas all remained susceptible to colistin, with MIC 50 and MIC 90 values of <0.5 mg/liter. The genes coding for carbapenemase production were identified by PCR and sequencing. OXA-23 enzymes (found in all centers) were by far the most common carbapenemases (81.7%), followed by OXA-58 oxacillinases (4.5%), which were found in 7 of the 25 centers. In 6 cases, CRAb isolates carried both bla OXA-23-like and bla OXA-58-like genes. A repetitive extragenic palindromic (REP)-PCR technique, multiplex PCRs for group identification, and multilocus sequence typing (MLST) were used to determine the genetic relationships among representative isolates (n ‫؍‬ 55). Two different clonal lineages were identified, including a dominant clone of sequence type 2 (ST2) related to the international clone II (sequence group 1 [SG1], SG4, and SG5) and a clone of ST78 (SG6) previously described in Italy. Overall, our results demonstrate that OXA-23 enzymes have become the most prevalent carbapenemases and are now endemic in Italy. In addition, molecular typing profiles showed the presence of international and national clonal lineages in Italy.

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Acinetobacter infection – an emerging threat to human health

2011

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SummaryThe genus Acinetobacter comprises a complex and heterogeneous group of bacteria, many of which are capable of causing a range of opportunistic, often catheter-related, infections in humans. However, Acinetobacter baumannii, as well as its close relatives belonging to genomic species 3 (''Acinetobacter pittii'') and 13TU (''Acinetobacter nosocomialis''), are important nosocomial pathogens, often associated with epidemic outbreaks of infection, that are only rarely found outside of a clinical setting. These organisms are frequently pandrug-resistant and are capable of causing substantial morbidity and mortality in patients with severe underlying disease, both in the hospital and in the community. Several epidemic clonal lineages of A. baumannii have disseminated worldwide and seem to have a selective advantage over non-epidemic strains. The reasons for the success of these epidemic lineages remain to be elucidated, but could be related to the potential of these organisms to achieve very dynamic reorganization and rapid evolution of their genome, including the acquisition and expression of additional antibiotic resistance determinants, under fluctuating environmental and selective conditions.

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Molecular Epidemiology of Multidrug-Resistant Acinetobacter baumannii in a Tertiary Care Hospital in Naples, Italy, Shows the Emergence of a Novel Epidemic Clone

Cited by 79 publications

References 26 publications

Clonal Diversity of Nosocomial Epidemic Acinetobacter baumannii Strains Isolated in Spain

Clonal Diversity of Nosocomial Epidemic Acinetobacter baumannii Strains Isolated in Spain

Epidemic Diffusion of OXA-23-Producing Acinetobacter baumannii Isolates in Italy: Results of the First Cross-Sectional Countrywide Survey

Acinetobacter infection – an emerging threat to human health

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