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Bourdin T, Benoit MÈ, Prévost M, Charron D, Quach C, Déziel E, Constant P, Bédard E. Disinfection of sink drains to reduce a source of three opportunistic pathogens, during Serratia marcescens clusters in a neonatal intensive care unit. PLoS One 2024; 19:e0304378. [PMID: 38865328 PMCID: PMC11168660 DOI: 10.1371/journal.pone.0304378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024] Open
Abstract
OBJECTIVE Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia marcescens, Pseudomonas aeruginosa and Stenotrophomonas maltophilia. DESIGN Over two years, three sampling campaigns were conducted in a neonatal intensive care unit (NICU). Samples from 19 sink drains were taken at three time points: before, during, and after disinfection. Bacterial concentration was measured using culture-based and flow cytometry methods. High-throughput short sequence typing was performed to identify the three OPs and assess S. marcescens persistence after disinfection at the genotypic level. SETTING This study was conducted in a pediatric hospitals NICU in Montréal, Canada, which is divided in an intensive and intermediate care side, with individual rooms equipped with a sink. INTERVENTIONS Five treatments were compared: self-disinfecting drains, chlorine disinfection, boiling water disinfection, hot tap water flushing, and steam disinfection. RESULTS This study highlights significant differences in the effectiveness of disinfection methods. Chlorine treatment proved ineffective in reducing bacterial concentration, including the three OPs. In contrast, all other drain interventions resulted in an immediate reduction in culturable bacteria (4-8 log) and intact cells (2-3 log). Thermal methods, particularly boiling water and steam treatments, exhibited superior effectiveness in reducing bacterial loads, including OPs. However, in drains with well-established bacterial biofilms, clonal strains of S. marcescens recolonized the drains after heat treatments. CONCLUSIONS Our study supports thermal disinfection (>80°C) for pathogen reduction in drains but highlights the need for additional trials and the implementation of specific measures to limit biofilm formation.
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Affiliation(s)
| | | | | | | | - Caroline Quach
- CHU Sainte-Justine, Université de Montréal, Montréal, QC, Canada
| | - Eric Déziel
- INRS-Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
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Alvaro A, Piazza A, Papaleo S, Perini M, Pasala AR, Panelli S, Nardi T, Nodari R, Sterzi L, Pagani C, Merla C, Castelli D, Olivieri E, Bracco S, Ferrando ML, Saluzzo F, Rimoldi SG, Corbella M, Cavallero A, Prati P, Farina C, Cirillo DM, Zuccotti G, Comandatore F. Cultivation and sequencing-free protocol for Serratia marcescens detection and typing. iScience 2024; 27:109402. [PMID: 38510115 PMCID: PMC10952028 DOI: 10.1016/j.isci.2024.109402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/08/2024] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Serratia marcescens is an opportunistic pathogen that survives in inhospitable environments causing large outbreaks, particularly in neonatal intensive care units (NICUs). Genomic studies revealed that most S. marcescens nosocomial infections are caused by a specific clone (here "Infectious clone"). Whole genome sequencing (WGS) is the only portable method able to identify this clone, but it requires days to obtain results. We present a cultivation-free hypervariable-locus melting typing (HLMT) protocol for the fast detection and typing of S. marcescens, with 100% detection capability on mixed samples and a limit of detection that can reach the 10 genome copies. The protocol was able to identify the S. marcescens infectious clone with 97% specificity and 96% sensitivity when compared to WGS, yielding typing results portable among laboratories. The protocol is a cost and time saving method for S. marcescens detection and typing for large environmental/clinical surveillance screenings, also in low-middle income countries.
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Affiliation(s)
- Alessandro Alvaro
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
- Department of Biosciences and Pediatric Clinical Research Center "Romeo Ed Enrica Invernizzi", University of Milan, 20133 Milan, Italy
| | - Aurora Piazza
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia 27100, Italy
| | - Stella Papaleo
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
| | - Matteo Perini
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Ajay Ratan Pasala
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
- Biochemistry, Microbiology and Immunology Department, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Centre for Innovation, Canadian Blood Services, Ottawa, ON K1G 4J5, Canada
| | - Simona Panelli
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
| | - Tiago Nardi
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy
| | - Riccardo Nodari
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
| | - Lodovico Sterzi
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
| | - Cristina Pagani
- Laboratorio di Microbiologia Clinica, Virologia e Diagnostica delle Bioemergenze, ASST Fatebenefratelli Sacco, 20157 Milan, Italy
| | - Cristina Merla
- Department of Microbiology & Virology, Fondazione IRCCS Policlinico San Matteo, Viale Camillo Golgi 19, 27100 Pavia, Italy
| | - Daniele Castelli
- Microbiology Unit, Fondazione IRCCS San Gerardo, 20900 Monza, Italy
| | - Emanuela Olivieri
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), 27100 Pavia, Italy
| | - Silvia Bracco
- Laboratory of Microbiology and Virology, Azienda Socio-Sanitaria Territoriale (ASST) Papa Giovanni XXIII, 24127 Bergamo, Italy
| | - Maria Laura Ferrando
- Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Francesca Saluzzo
- Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Sara Giordana Rimoldi
- Laboratorio di Microbiologia Clinica, Virologia e Diagnostica delle Bioemergenze, ASST Fatebenefratelli Sacco, 20157 Milan, Italy
| | - Marta Corbella
- Department of Microbiology & Virology, Fondazione IRCCS Policlinico San Matteo, Viale Camillo Golgi 19, 27100 Pavia, Italy
| | | | - Paola Prati
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), 27100 Pavia, Italy
| | - Claudio Farina
- Laboratory of Microbiology and Virology, Azienda Socio-Sanitaria Territoriale (ASST) Papa Giovanni XXIII, 24127 Bergamo, Italy
| | - Daniela Maria Cirillo
- Emerging Bacterial Pathogens Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Gianvincenzo Zuccotti
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
- Department of Paediatrics, Children’s Hospital "V. Buzzi", 20154 Milano, Italy
| | - Francesco Comandatore
- Department of Biomedical and Clinical Sciences, Pediatric Clinical Research Center “Romeo and Enrica Invernizzi”, University of Milan, 20157 Milan, Italy
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Bourdin T, Benoit MÈ, Bédard E, Prévost M, Quach C, Déziel E, Constant P. High-Throughput Short Sequence Typing Schemes for Pseudomonas aeruginosa and Stenotrophomonas maltophilia Pure Culture and Environmental DNA. Microorganisms 2023; 12:48. [PMID: 38257875 PMCID: PMC10819370 DOI: 10.3390/microorganisms12010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024] Open
Abstract
Molecular typing techniques are utilized to determine genetic similarities between bacterial isolates. However, the use of environmental DNA profiling to assess epidemiologic links between patients and their environment has not been fully explored. This work reports the development and validation of two high-throughput short sequence typing (HiSST) schemes targeting the opportunistic pathogens Pseudomonas aeruginosa and Stenotrophomonas maltophilia, along with a modified SM2I selective medium for the specific isolation of S. maltophilia. These HiSST schemes are based on four discriminative loci for each species and demonstrate high discriminating power, comparable to pairwise whole-genome comparisons. Each scheme includes species-specific PCR primers for precise differentiation from closely related taxa, without the need for upstream culture-dependent methods. For example, the primers targeting the bvgS locus make it possible to distinguish P. aeruginosa from the very closely related Pseudomonas paraeruginosa sp. nov. The selected loci included in the schemes are adapted to massive parallel amplicon sequencing technology. An R-based script implemented in the DADA2 pipeline was assembled to facilitate HiSST analyses for efficient and accurate genotyping of P. aeruginosa and S. maltophilia. We demonstrate the performance of both schemes through in silico validations, assessments against reference culture collections, and a case study involving environmental samples.
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Affiliation(s)
- Thibault Bourdin
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada;
| | - Marie-Ève Benoit
- CHU Sainte-Justine Research Center, Montréal, QC H3T 1C5, Canada; (M.-È.B.); (C.Q.)
| | - Emilie Bédard
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC H3T 1J4, Canada; (E.B.); (M.P.)
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC H3T 1J4, Canada; (E.B.); (M.P.)
| | - Caroline Quach
- CHU Sainte-Justine Research Center, Montréal, QC H3T 1C5, Canada; (M.-È.B.); (C.Q.)
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada;
| | - Philippe Constant
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada;
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Bourdin T, Benoit MÈ, Monnier A, Bédard E, Prévost M, Charron D, Audy N, Gravel S, Sicard M, Quach C, Déziel E, Constant P. Serratia marcescens Colonization in a Neonatal Intensive Care Unit Has Multiple Sources, with Sink Drains as a Major Reservoir. Appl Environ Microbiol 2023; 89:e0010523. [PMID: 37067412 PMCID: PMC10231179 DOI: 10.1128/aem.00105-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/27/2023] [Indexed: 04/18/2023] Open
Abstract
Compelling evidence suggests a contribution of the sink environment to the transmission of opportunistic pathogens from the hospital environment to patients in neonatal intensive care units (NICU). In this study, the distribution of the opportunistic pathogen Serratia marcescens in the sink environment and newborns in a NICU was investigated. More than 500 sink drain and faucet samples were collected over the course of five sampling campaigns undertaken over 3 years. Distribution and diversity of S. marcescens were examined with a modified MacConkey medium and a high-throughput short-sequence typing (HiSST) method. Sink drains were an important reservoir of S. marcescens, with an average of 44% positive samples, whereas no faucet sample was positive. The genotypic diversity of S. marcescens was moderate, with an average of two genotypes per drain, while the spatial distribution of S. marcescens was heterogeneous. The genotypic profiles of 52 clinical isolates were highly heterogeneous, with 27 unique genotypes, of which 71% of isolates were found in more than one patient. S. marcescens acquisition during the first outbreaks was mainly caused by horizontal transmissions. HiSST analyses revealed 10 potential cases of patient-to-patient transmission of S. marcescens, five cases of patient-to-sink transmission, and one bidirectional transfer between sink and patient. Environmental and clinical isolates were found in sink drains up to 1 year after the first detection, supporting persisting drain colonization. This extensive survey suggests multiple reservoirs of S. marcescens within the NICU, including patients and sink drains, but other external sources should also be considered. IMPORTANCE The bacterium Serratia marcescens is an important opportunistic human pathogen that thrives in many environments, can become multidrug resistant, and is often involved in nosocomial outbreaks in neonatal intensive care units (NICU). We evaluated the role of sinks during five suspected S. marcescens outbreaks in a NICU. An innovative approach combining molecular and culture methods was used to maximize the detection and typing of S. marcescens in the sink environment. Our results indicate multiple reservoirs of S. marcescens within the NICU, including patients, sink drains, and external sources. These results highlight the importance of sinks as a major reservoir of S. marcescens and potential sources of future outbreaks.
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Affiliation(s)
- Thibault Bourdin
- INRS–Centre Armand-Frappier Santé Biotechnologie, Laval, Quebec, Canada
| | | | - Alizée Monnier
- INRS–Centre Armand-Frappier Santé Biotechnologie, Laval, Quebec, Canada
| | | | | | | | - Nathalie Audy
- CHU Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada
| | - Sophie Gravel
- CHU Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada
| | - Mélanie Sicard
- CHU Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada
| | - Caroline Quach
- CHU Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada
| | - Eric Déziel
- INRS–Centre Armand-Frappier Santé Biotechnologie, Laval, Quebec, Canada
| | - Philippe Constant
- INRS–Centre Armand-Frappier Santé Biotechnologie, Laval, Quebec, Canada
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Lara E, Singer D, Geisen S. Discrepancies between prokaryotes and eukaryotes need to be considered in soil DNA-based studies. Environ Microbiol 2022; 24:3829-3839. [PMID: 35437903 PMCID: PMC9790305 DOI: 10.1111/1462-2920.16019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 12/30/2022]
Abstract
Metabarcoding approaches are exponentially increasing our understanding of soil biodiversity, with a major focus on the bacterial part of the microbiome. Part of the soil diversity are also eukaryotes that include fungi, algae, protists and Metazoa. Nowadays, soil eukaryotes are targeted with the same approaches developed for bacteria and archaea (prokaryotes). However, fundamental differences exist between domains. After providing a short historical overview of the developments of metabarcoding applied to environmental microbiology, we compile the most important differences between domains that prevent direct method transfers between prokaryotic and eukaryotic soil metabarcoding approaches, currently dominated by short-read sequencing. These include the existence of divergent diversity concepts and the variations in eukaryotic morphology that affect sampling and DNA extraction. Furthermore, eukaryotes experienced much more variable evolutionary rates than prokaryotes, which prevent capturing the entire eukaryotic diversity in a soil with a single amplification protocol fit for short-read sequencing. In the final part we focus on future potentials for optimization of eukaryotic metabarcoding that include superior possibility of functionally characterizing eukaryotes and to extend the current information obtained, such as by adding a real quantitative component. This review should optimize future metabarcoding approaches targeting soil eukaryotes and kickstart this promising research direction.
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Affiliation(s)
- Enrique Lara
- Real Jardín Botánico‐CSIC, Plaza de Murillo 2Madrid28014Spain
| | - David Singer
- UMR CNRS 6112 LPG‐BIAFAngers University, 2 Boulevard LavoisierAngers49045France
| | - Stefan Geisen
- Laboratory of NematologyWageningen UniversityWageningen6700 AAThe Netherlands
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Genomic characterisation of an entomopathogenic strain of Serratia ureilytica in the critically endangered phasmid Dryococelus australis. PLoS One 2022; 17:e0265967. [PMID: 35442959 PMCID: PMC9020675 DOI: 10.1371/journal.pone.0265967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 03/10/2022] [Indexed: 11/19/2022] Open
Abstract
Between 2014 and 2019, unexpected mortalities were observed in a colony of Dryococelus australis, an endangered stick-insect kept at the Melbourne Zoo for a breeding and conservation program. Pure cultures of Serratia spp. were obtained from the haemolymph of moribund and recently deceased individuals. The combined bacteriological and histopathological observations suggested an infectious cause of these mortalities. Genotyping of Serratia sp. isolated from the insects and their environment revealed a predominant strain profile. A representative isolate, AM923, was entirely sequenced and compared to 616 publicly available Serratia spp. genomes, including 37 associated with insects. The genomes were distributed into 3 distinct groups, with 63% of the insect-associated isolates within a single clade (clade A) containing AM923, separated from most environmental/plant-associated strains (clade B) and human isolates (clade C). Average nucleotide identity and phylogenetic analyses identified AM923 as S. ureilytica and revealed similarities with putatively entomopathogenic strains. An experimental infection model in honey bees (Apis mellifera) confirmed the pathogenic potential of AM923. A urease operon was found in most insect isolates and a PCR assay, based on the ureB gene sequence, was used to confirm the presence of AM923 in experimentally infected bees. This species-specific PCR could be applied to detect entomopathogenic Serratia spp. in infected insects or their environment.
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Allen JL, Doidge NP, Bushell RN, Browning GF, Marenda MS. Healthcare-associated infections caused by chlorhexidine-tolerant Serratia marcescens carrying a promiscuous IncHI2 multi-drug resistance plasmid in a veterinary hospital. PLoS One 2022; 17:e0264848. [PMID: 35298517 PMCID: PMC8929579 DOI: 10.1371/journal.pone.0264848] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/17/2022] [Indexed: 11/19/2022] Open
Abstract
The bacterium Serratia marcescens can cause opportunistic infections in humans and in animals. In veterinary settings, the diversity, reservoirs and modes of transmission of this pathogen are poorly understood. The phenotypes and genotypes of Serratia spp. isolated from dogs, cats, horses, a bird and a rabbit examined at an Australian veterinary hospital between 2008 and 2019 were characterised. The isolates were identified as S. marcescens (n = 15) or S. ureilytica (n = 3) and were placed into four distinct phylogenetic groups. Nine quasi-clonal isolates associated with post-surgical complications in different patients displayed high levels of resistance to the antimicrobials fluoroquinolones, cephalosporins, aminoglycosides, and to the disinfectant chlorhexidine. A Serratia sp. with a similar resistance profile was also isolated from chlorhexidine solutions used across the Hospital, suggesting that these infections had a nosocomial origin. A genomic island encoding a homolog of the Pseudomonas MexCD-OprJ biocide efflux system was detected in the chlorhexidine-tolerant Serratia. The nine multi-drug resistant Serratia isolates also possessed a Ser-83-Ile mutation in GyrA conferring fluoroquinolone resistance, and carried a large IncHI2 conjugative plasmid encoding antimicrobial and heavy metal resistances. This replicon was highly similar to a plasmid previously detected in a strain of Enterobacter hormaechei recovered from the Hospital environment. IncHI2 plasmids are commonly found in Enterobacteriaceae, but are rarely present in Serratia spp., suggesting that this plasmid was acquired from another organism. A chlorhexidine-tolerant Serratia isolate which lacked the IncHI2 plasmid was used in mating experiments to demonstrate the transfer of multi-drug resistance from a E. hormaechei donor. This study illustrates the importance of environmental surveillance of biocide-resistance in veterinary hospitals.
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Affiliation(s)
- Joanne L. Allen
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Nicholas P. Doidge
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Rhys N. Bushell
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Glenn F. Browning
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Marc S. Marenda
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
- * E-mail:
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Dahdouh E, Lázaro-Perona F, Ruiz-Carrascoso G, Sánchez García L, Saenz de Pipaón M, Mingorance J. Intestinal Dominance by Serratia marcescens and Serratia ureilytica among Neonates in the Setting of an Outbreak. Microorganisms 2021; 9:microorganisms9112271. [PMID: 34835397 PMCID: PMC8624583 DOI: 10.3390/microorganisms9112271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/22/2021] [Accepted: 10/29/2021] [Indexed: 11/20/2022] Open
Abstract
(1) Background: We determined the relevance of intestinal dominance by Serratia spp. during a neonatal outbreak over 13 weeks. (2) Methods: Rectal swabs (n = 110) were obtained from 42 neonates. Serratia spp. was cultured from swabs obtained from 13 neonates (Group 1), while the other 29 neonates were culture-negative (Group 2). Total DNA was extracted from rectal swabs, and quantitative PCRs (qPCRs) using Serratia- and 16SrRNA-gene-specific primers were performed. relative intestinal loads (RLs) were determined using ΔΔCt. Clonality was investigated by random amplified polymorphic DNA analysis and whole-genome sequencing. (3) Results: The outbreak was caused by Serratia marcescens during the first eight weeks and Serratia ureilytica during the remaining five weeks. Serratia spp. were detected by qPCR in all Group 1 neonates and eleven Group 2 neonates. RLs of Serratia spp. were higher in Group 1 as compared to Group 2 (6.31% vs. 0.09%, p < 0.05) and in the first swab compared to the last (26.9% vs. 4.37%, p < 0.05). Nine neonates had extraintestinal detection of Serratia spp.; eight of them were infected. RLs of the patients with extraintestinal spread were higher than the rest (2.79% vs. 0.29%, p < 0.05). (4) Conclusions: Intestinal dominance by Serratia spp. plays a role in outbreaks and extraintestinal spread.
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Affiliation(s)
- Elias Dahdouh
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, Paseo de la Castellana, 261, 28046 Madrid, Spain; (F.L.-P.); (G.R.-C.); (J.M.)
- Correspondence: ; Tel.: +34-917-277-000
| | - Fernando Lázaro-Perona
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, Paseo de la Castellana, 261, 28046 Madrid, Spain; (F.L.-P.); (G.R.-C.); (J.M.)
| | - Guillermo Ruiz-Carrascoso
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, Paseo de la Castellana, 261, 28046 Madrid, Spain; (F.L.-P.); (G.R.-C.); (J.M.)
| | - Laura Sánchez García
- Servicio de Neonatología, Hospital Universitario La Paz, 28046 Madrid, Spain; (L.S.G.); (M.S.d.P.)
| | - Miguel Saenz de Pipaón
- Servicio de Neonatología, Hospital Universitario La Paz, 28046 Madrid, Spain; (L.S.G.); (M.S.d.P.)
| | - Jesús Mingorance
- Servicio de Microbiología, Hospital Universitario La Paz, IdiPAZ, Paseo de la Castellana, 261, 28046 Madrid, Spain; (F.L.-P.); (G.R.-C.); (J.M.)
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