Occurrence of Legionella in groundwater used for sprinkler irrigation in Southern Italy.

Legionellae are opportunistic bacteria that cause various conditions after exposure to contaminated aerosols, ranging from a serious type of pneumonia to a mild case of an influenza-like illness. Despite the risks of exposure, little is known about the occurrence of Legionella in natural environments and, even though studies have shown that there is a potential risk of transmission via inhalation, it does not have to be detected in groundwater that is used for irrigation. The culture methods traditionally used to detect Legionella have several limits that can be partly solved by applying molecular techniques. Samples from 177 wells in Apulia, Southern Italy, were collected twice, in winter and in summer, and analyzed. When compared with the guidelines, 145 (81.9%) of the sampled wells were suitable for irrigation use. The culture-based method highlighted the presence of different species and serogroups of Legionella in 31 (21.2%) of the 145 wells that were shown to be suitable for irrigation use. A greater number of wells returned positive results for Legionella in summer than in winter (p = 0.023), and the median concentrations were mostly higher in summer (500 CFU/L) than in winter (300 CFU/L). The median temperature in the Legionella positive well waters was significantly higher than that in the negative ones, both in winter and in summer (p < 0.001). Using molecular techniques, Legionella non-pneumophila was found in 37 of the 114 wells earlier detected as suitable for irrigation use but negative for Legionella by the culture-based methods. The distribution of Legionella differ significantly in porous aquifers compared to the karst-fissured ones both with quantitative polymerase chain reaction (qPCR) (p = 0.0004) and viable cells by propidium monoazide (PMA-qPCR) (p = 0.0000). Legionella concentrations were weakly correlated with temperature of water both with qPCR (ρ = 0.47, p = 0.0033) and PMA-qPCR (ρ = 0.41, p = 0.0126). Our data suggest that water that aerosolizes when sprinkled on plants represents a potential source of Legionellosis, with a higher risk from exposure in summer. On a practical level, this finding is important for workers (farmers and gardeners) who are in contact with waters used for irrigation.

Editorial for the Special Issue "Antimicrobial Resistance and Genetic Elements in Bacteria".

Throughout human history, bacterial infections have been an omnipresent threat, which have, on occasion, resulted in devastating pandemics affecting humanity [...].

Bioinformatic survey of CRISPR loci across 15 Serratia species.

The Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated proteins (CRISPR-Cas) system of prokaryotes is an adaptative immune defense mechanism to protect themselves from invading genetic elements (e.g., phages and plasmids). Studies that describe the genetic organization of these prokaryotic systems have mainly reported on the Enterobacteriaceae family (now reorganized within the order of Enterobacterales). For some genera, data on CRISPR-Cas systems remain poor, as in the case of Serratia (now part of the Yersiniaceae family) where data are limited to a few genomes of the species marcescens. This study describes the detection, in silico, of CRISPR loci in 146 Serratia complete genomes and 336 high-quality assemblies available for the species ficaria, fonticola, grimesii, inhibens, liquefaciens, marcescens, nematodiphila, odorifera, oryzae, plymuthica, proteomaculans, quinivorans, rubidaea, symbiotica, and ureilytica. Apart from subtypes I-E and I-F1 which had previously been identified in marcescens, we report that of I-C and the I-E unique locus 1, I-E*, and I-F1 unique locus 1. Analysis of the genomic contexts for CRISPR loci revealed mdtN-phnP as the region mostly shared (grimesii, inhibens, marcescens, nematodiphila, plymuthica, rubidaea, and Serratia sp.). Three new contexts detected in genomes of rubidaea and fonticola (puu genes-mnmA) and rubidaea (osmE-soxG and ampC-yebZ) were also found. The plasmid and/or phage origin of spacers was also established.

"Ectomosphere": Insects and Microorganism Interactions.

This study focuses on interacting with insects and their ectosymbiont (lato sensu) microorganisms for environmentally safe plant production and protection. Some cases help compare ectosymbiont microorganisms that are insect-borne, -driven, or -spread relevant to endosymbionts' behaviour. Ectosymbiotic bacteria can interact with insects by allowing them to improve the value of their pabula. In addition, some bacteria are essential for creating ecological niches that can host the development of pests. Insect-borne plant pathogens include bacteria, viruses, and fungi. These pathogens interact with their vectors to enhance reciprocal fitness. Knowing vector-phoront interaction could considerably increase chances for outbreak management, notably when sustained by quarantine vector ectosymbiont pathogens, such as the actual Xylella fastidiosa Mediterranean invasion episode. Insect pathogenic viruses have a close evolutionary relationship with their hosts, also being highly specific and obligate parasites. Sixteen virus families have been reported to infect insects and may be involved in the biological control of specific pests, including some economic weevils. Insects and fungi are among the most widespread organisms in nature and interact with each other, establishing symbiotic relationships ranging from mutualism to antagonism. The associations can influence the extent to which interacting organisms can exert their effects on plants and the proper management practices. Sustainable pest management also relies on entomopathogenic fungi; research on these species starts from their isolation from insect carcasses, followed by identification using conventional light or electron microscopy techniques. Thanks to the development of omics sciences, it is possible to identify entomopathogenic fungi with evolutionary histories that are less-shared with the target insect and can be proposed as pest antagonists. Many interesting omics can help detect the presence of entomopathogens in different natural matrices, such as soil or plants. The same techniques will help localize ectosymbionts, localization of recesses, or specialized morphological adaptation, greatly supporting the robust interpretation of the symbiont role. The manipulation and modulation of ectosymbionts could be a more promising way to counteract pests and borne pathogens, mitigating the impact of formulates and reducing food insecurity due to the lesser impact of direct damage and diseases. The promise has a preventive intent for more manageable and broader implications for pests, comparing what we can obtain using simpler, less-specific techniques and a less comprehensive approach to Integrated Pest Management (IPM).

Identification and Characterisation of pST1023 A Mosaic, Multidrug-Resistant and Mobilisable IncR Plasmid.

We report the identification and characterisation of a mosaic, multidrug-resistant and mobilisable IncR plasmid (pST1023) detected in Salmonella ST1023, a monophasic variant 4,[5],12:i: strain of widespread pandemic lineage, reported as a Southern European clone. pST1023 contains exogenous DNA regions, principally gained from pSLT-derivatives and IncI1 plasmids. Acquisition from IncI1 included oriT and nikAB and these conferred the ability to be mobilisable in the presence of a helper plasmid, as we demonstrated with the conjugative plasmids pST1007-1D (IncFII) or pVC1035 (IncC). A sul3-associated class 1 integron, conferring resistance to aminoglycosides, chloramphenicol and trimethoprim-sulphonamides, was also embedded in the acquired IncI1 DNA segment. pST1023 also harboured an additional site-specific recombination system (rfsF/rsdB) and IS elements of the IS1, IS5 (IS903 group) and IS6 families. Four of the six IS26 elements present constituted two pseudo-compound-transposons, named PCT-sil and PCT-Tn10 (identified here for the first time). The study further highlighted the mosaic genetic architecture and the clinical importance of IncR plasmids. Moreover, it provides the first experimental data on the ability of IncR plasmids to be mobilised and their potential role in the horizontal spread of antimicrobial-resistant genes.

Cholera in Ethiopia in the 1990 s: epidemiologic patterns, clonal analysis, and antimicrobial resistance.

In 1993, after 6 years of absence, cholera re-emerged in the Horn of Africa. Following its introduction to Djibouti, the disease spread to the central and southern areas of Ethiopia reaching Somalia in 1994. Cholera outbreaks persisted in Ethiopia with a recrudescence of cases in 1998. Twenty-two Vibrio cholerae O1 strains, selected to represent the 1998 history of cholera in Ethiopia, were characterized by random amplified polymorphic DNA patterns, BglI ribotyping and antimicrobial susceptibility. All isolates showed a unique amplified DNA pattern and a prevalent ribotype B8a. All strains were multidrug-resistant and harboured an IncC plasmid which conferred resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and trimethoprim. These findings indicate that a group of closely related V. cholerae O1 strains was responsible for the cholera epidemic in Ethiopia in 1998.

Clonal relationship among Vibrio cholerae O1 El Tor strains isolated in Somalia.

One hundred and three Vibrio cholerae O1 strains, selected to represent the cholera outbreaks which occurred in Somalia in 1998-1999, were characterized by random amplified polymorphic DNA patterns, ribotyping, and antimicrobial susceptibility. All strains showed a unique amplified DNA pattern and 2 closely related ribotypes (B5a and B8a), among which B5a was the more frequently identified. Ninety-one strains were resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfamethoxazole, and trimethoprim, conferred, except for spectinomycin, by a conjugative plasmid IncC. These findings indicated that the group of strains active in Somalia in the late 1990s had a clonal origin.

Characterization of CRISPR-Cas Systems in Serratia marcescens Isolated from Rhynchophorus ferrugineus (Olivier, 1790) (Coleoptera: Curculionidae).

The CRISPR-Cas adaptive immune system has been attracting increasing scientific interest for biological functions and biotechnological applications. Data on the Serratia marcescens system are scarce. Here, we report a comprehensive characterisation of CRISPR-Cas systems identified in S. marcescens strains isolated as secondary symbionts of Rhynchophorus ferrugineus, also known as Red Palm Weevil (RPW), one of the most invasive pests of major cultivated palms. Whole genome sequencing was performed on four strains (S1, S5, S8, and S13), which were isolated from the reproductive apparatus of RPWs. Subtypes I-F and I-E were harboured by S5 and S8, respectively. No CRISPR-Cas system was detected in S1 or S13. Two CRISPR arrays (4 and 51 spacers) were detected in S5 and three arrays (11, 31, and 30 spacers) were detected in S8. The CRISPR-Cas systems were located in the genomic region spanning from ybhR to phnP, as if this were the only region where CRISPR-Cas loci were acquired. This was confirmed by analyzing the S. marcescens complete genomes available in the NCBI database. This region defines a genomic hotspot for horizontally acquired genes and/or CRISPR-Cas systems. This study also supplies the first identification of subtype I-E in S. marcescens.

Human health risk assessment for the occurrence of enteric viruses in drinking water from wells: Role of flood runoff injections.

We demonstrated that floods can induce severe microbiological contamination of drinking water from wells and suggest strategies to better address water safety plans for groundwater drinking supplies. Since 2002, the Italian Water Research Institute (IRSA) has detected hepatitis A virus, adenovirus, rotavirus, norovirus, and enterovirus in water samples from wells in the Salento peninsula, southern Italy. Perturbations in the ionic strength in water flow can initiate strong virus detachments from terra rossa sediments in karst fractures. This study therefore explored the potential health impacts of prolonged runoff injections in Salento groundwater caused by severe flooding during October 2018. A mathematical model for virus fate and transport in fractures was applied to determine the impact of floodwater injection on groundwater quality by incorporating mechanisms that affect virus attachment/detachment and survival in flowing water at microscale. This model predicted target concentrations of enteric viruses that can occur unexpectedly in wells at considerable distances (5-8 km) from the runoff injection site (sinkhole). Subsequently, the health impact of viruses in drinking water supplied from contaminated wells was estimated during the summer on the Salento coast. Specific unpublished dose-response model coefficients were proposed to determine the infection probabilities for Echo-11 and Polio 1 enteroviruses through ingestion. The median (50%) risk of infection was estimated at 6.3 ·â€¯10-3 with an uncertainty of 23%. The predicted burden of diseases was 4.89 disability adjusted life years per year, i.e., twice the maximum tolerable disease burden. The results highlight the requirement for additional water disinfection treatments in Salento prior to the distribution of drinking water. Moreover, monthly controls of enteric virus occurrence in water from wells should be imposed by a new water framework directive in semiarid regions because of the vulnerability of karst carbonate aquifers to prolonged floodwater injections and enteric virus contamination.

Carbapenemases-producing Klebsiella pneumoniae in hospitals of two regions of Southern Italy.

Carbapenem-resistant Klebsiella pneumoniae infections are reported with increasing frequency elsewhere in the world, representing a worrying phenomenon for global health. In Italy, there are hotspot data on the diffusion and type of carbapenemase-producing Enterobacteriaceae and K. pneumoniae in particular, with very few data coming from Apulia and Basilicata, two regions of Southern Italy. This study was aimed at characterizing by phenotypic and genotypic methods carbapenem-resistant K. pneumoniae isolated from several Hospitals of Apulia and Basilicata, Southern Italy. Antibiotic susceptibility was also evaluated. The relatedness of carbapenemase-producing K. pneumoniae strains was established by pulsed-field gel electrophoresis (PFGE). Among the 150 K. pneumoniae carbapenemase producers, KPC-3 genotype was the most predominant (95%), followed by VIM-1 (5%). No other genotypes were found and no co-presence of two carbapenemase genes was found. A full concordance between results obtained by both the phenotypic and the genotypic tests was observed. All strains were resistant to ß-lactam antibiotics including carbapenems, and among antibiotics tested, only tetracycline and gentamycin showed low percentage of resistance (18% and 15%, respectively). Resistance to colistin was detected in 17.3% of strains studied. The analysis of PFGE profiles of the carbapenemases-positive strains shows that one group (B) of the five (A to E) main groups identified was the most prevalent and detected in almost all the hospitals considered, while the other groups were randomly distributed. Three different sequence types (ST 307, ST 258, and ST 512) were detected with the majority of isolates belonging to the ST 512. Our results demonstrated the wide diffusion of K. pneumoniae KPC-3 in the area considered, the good concordance between phenotypic and genotypic tests. Gentamicin and colistin had a good activity against these strains.

Molecular epidemiology and origin of cholera reemergence in Italy and Albania in the 1990s.

In 1994 a cholera epidemic occurred in Italy and Albania after more than a decade of case absence. To investigate genotypic characteristics and the origin of the epidemic strains, 110 Vibrio cholerae O1 El Tor isolates from Italy and Albania were studied by randomly amplified polymorphic DNA analysis (RAPD), BglI ribotyping, and pulsed-field gel electrophoresis (PFGE) of genomic DNA. The Italian and Albanian strains were all ribotype 6 and their RAPD and PFGE patterns were identical as well. These findings indicated that the 1994 isolates belonged to the same clone and that the clone was part of the larger global spread of epidemic ribotype 6 strains, which started in southern Asia in 1990.

Identification of pigmented Serratia marcescens symbiotically associated with Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae).

To characterize red pigment-producing bacteria (RPPB) regularly released during oviposition by red palm weevil (RPW), RPPB were recovered from eggs deposited in apples supplied as substrate for oviposition. The presence of RPPB was also detected from gut, the reproductive apparatus of dissected adult and virgin insects and from pupal cases collected within infested palms. RPPB were also identified all along the tissue of these palms. Analysis of the 16S rDNA, gyrB, rpoB, recA, and groEL sequences assigned RPPB to the species Serratia marcescens. RPPB exhibited an antimicrobial activity assessed by the agar well diffusion method against a number of gram-positive and gram-negative bacteria. In this study, we first report the identification of a red pigment-producing S. marcescens as extracellular symbiont of RPW. Route of transmission, detection within different organs, and a wide spread along the infested palm tissue, suggested S. marcescens is present as extracellular symbiont in different developmental stages of the RPW. Additionally, the antimicrobial activity exhibited versus Bacillus spp., Paenibacillus spp., and Lysinibacillus spp., reported as insect pathogens and potential candidates for biocontrol agents, could ascribe for S. marcescens a potential protective role.

Susceptibility to rifaximin of Vibrio cholerae strains from different geographical areas.

Four hundred and eight clinical strains of Vibrio cholerae isolated from different geographical areas and with different antimicrobial resistance patterns were tested for susceptibility to rifaximin, a non-absorbable antibiotic active in vitro against Gram-negative bacteria. The MICs ranged from 0.5 to 4 mg/l for all strains. These values and the pharmacokinetic properties suggest rifaximin as an attractive antimicrobial agent for cholera.