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Harmer CJ, Cahill SM, Kenyon JJ, Hall RM. Aminoglycoside resistance genes in early members of the Acinetobacter baumannii ST78A (SMAL, Italian clone) reside in an IS26-bounded island in the chromosome. J Antimicrob Chemother 2024; 79:1014-1018. [PMID: 38530861 PMCID: PMC11062947 DOI: 10.1093/jac/dkae064] [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: 10/30/2023] [Accepted: 02/13/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND The Acinetobacter baumannii isolate called SMAL, previously used to determine the structures of capsular polysaccharide and lipooligosaccharide, was recovered in Pavia, Italy in 2002 among the collection of aminoglycoside-resistant isolates designated as SMAL type. This type was later called the Italian clone, then ST78. ST78 isolates are now widely distributed. OBJECTIVES To establish the resistance gene complement and the location and structure of acquired resistance regions in early members of the Italian/ST78 clone. METHODS The draft genome of SMAL2002 was assembled from Illumina MiSeq reads. Contigs containing resistance genes were joined and located in the chromosome using PCR with custom primers. The resistance profile was determined using disc diffusion. RESULTS SMAL2002 is an ST78A isolate and includes three aminoglycoside resistance genes, aadB (gentamicin, kanamycin, tobramycin) aphA1 (kanamycin, neomycin) and aac(6')-Ian (amikacin, kanamycin, tobramycin). The aadB gene cassette is incorporated at a secondary site in a relative of the aphA1-containing, IS26-bounded pseudo-compound transposon, PTn6020. The aac(6')-Ian gene is in an adjacent IS26-bounded structure that includes sul2 (sulphonamide) and floR (florfenicol) resistance genes. The two pseudo-compound transposons overlap and are in the chromosomal hutU gene flanked by an 8 bp target site duplication. Although aac(6')-Ian was not noticed previously, the same genes and structures were found in several available draft genomes of early ST78A isolates. CONCLUSIONS This study highlights the importance of correlating resistance profiles with resistance gene content. The location of acquired resistance genes in the SMAL2002 chromosome represents the original location in the ST78A lineage of ST78.
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Affiliation(s)
- Christopher J Harmer
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2008, Australia
| | - Sarah M Cahill
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Johanna J Kenyon
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Ruth M Hall
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2008, Australia
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Sohrabi M, Pirbonyeh N, Alizade Naini M, Rasekhi A, Ayoub A, Hashemizadeh Z, Shahcheraghi F. A challenging case of carbapenem resistant Klebsiella pneumoniae-related pyogenic liver abscess with capsular polysaccharide hyperproduction: a case report. BMC Infect Dis 2024; 24:433. [PMID: 38654215 PMCID: PMC11040961 DOI: 10.1186/s12879-024-09314-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 04/11/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a major public health problem, necessitating the administration of polymyxin E (colistin) as a last-line antibiotic. Meanwhile, the mortality rate associated with colistin-resistant K. pneumoniae infections is seriously increasing. On the other hand, importance of administration of carbapenems in promoting colistin resistance in K. pneumoniae is unknown. CASE PRESENTATION We report a case of K. pneumoniae-related pyogenic liver abscess in which susceptible K. pneumoniae transformed into carbapenem- and colistin-resistant K. pneumoniae during treatment with imipenem. The case of pyogenic liver abscess was a 50-year-old man with diabetes and liver transplant who was admitted to Abu Ali Sina Hospital in Shiraz. The K. pneumoniae isolate responsible for community-acquired pyogenic liver abscess was isolated and identified. The K. pneumoniae isolate was sensitive to all tested antibiotics except ampicillin in the antimicrobial susceptibility test and was identified as a non-K1/K2 classical K. pneumoniae (cKp) strain. Multilocus sequence typing (MLST) identified the isolate as sequence type 54 (ST54). Based on the patient's request, he was discharged to continue treatment at another center. After two months, he was readmitted due to fever and progressive constitutional symptoms. During treatment with imipenem, the strain acquired blaOXA-48 and showed resistance to carbapenems and was identified as a multidrug resistant (MDR) strain. The minimum inhibitory concentration (MIC) test for colistin was performed by broth microdilution method and the strain was sensitive to colistin (MIC < 2 µg/mL). Meanwhile, on blood agar, the colonies had a sticky consistency and adhered to the culture medium (sticky mucoviscous colonies). Quantitative real-time PCR and biofilm formation assay revealed that the CRKP strain increased capsule wzi gene expression and produced slime in response to imipenem. Finally, K. pneumoniae-related pyogenic liver abscess with resistance to a wide range of antibiotics, including the last-line antibiotics colistin and tigecycline, led to sepsis and death. CONCLUSIONS Based on this information, can we have a theoretical hypothesis that imipenem is a promoter of resistance to carbapenems and colistin in K. pneumoniae? This needs more attention.
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Affiliation(s)
- Maryam Sohrabi
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Neda Pirbonyeh
- Department of Microbiology, Burn and Wound Healing Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahvash Alizade Naini
- Department of Internal Medicine, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alireza Rasekhi
- Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Abbas Ayoub
- Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Hashemizadeh
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
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Usman M, Marcus A, Fatima A, Aslam B, Zaid M, Khattak M, Bashir S, Masood S, Rafaque Z, Dasti JI. Synergistic Effects of Gentamicin, Cefepime, and Ciprofloxacin on Biofilm of Pseudomonas aeruginosa. Infect Drug Resist 2023; 16:5887-5898. [PMID: 37692466 PMCID: PMC10485136 DOI: 10.2147/idr.s426111] [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: 07/11/2023] [Accepted: 08/19/2023] [Indexed: 09/12/2023] Open
Abstract
Background Pseudomonas aeruginosa is an opportunistic pathogen involved in number of hospital-acquired infections such as catheter-associated urinary tract infections, bacteremia, septicemia, skin infections, and ventilator-associated pneumoniae. Biofilm formation is an important trait implicated in chronic infections, such as cystic fibrosis and chronic pulmonary obstruction. We evaluated effects of gentamicin, cefepime, and ciprofloxacin on biofilm of P. aeruginosa. Materials and Methods A total of 266 isolates were collected from the Armed Forces Institute of Pathology (AFIP). Antibiotic susceptibility was assessed by double disk synergy testing. ESBL and carbapenemase detection was performed by phenotypic testing. Molecular screening of the genes was done by PCR. Micro-dilution broth method was used to determine minimum inhibitory concentrations of antibiotics. Biofilm formation was done by micro-titer plate assay. Results Overall, 20% of the P. aeruginosa isolates were extensively drug-resistant (XDR-PA), and 25% were multi-drug-resistant (MDR-PA). Likewise, 43% of the isolates were ESBL producers, and carbapenemase production was detected in 40% of the isolates. Molecular analysis confirmed occurrence of different resistant factors in ESBL-positive isolates; 67% carried blaTEM, 62% blaCTXM-15, 41% blaSHV, 34% blaCTXM-14, and 33% blaOXA-1. In addition, 68% of the carbapenem-resistant isolates were positive for blaNDM-1, 25% for blaOXA-48, and 22% for blaKPC-2. Biofilm formation was assessed for 234 isolates, out of which 28% were strong biofilm formers. Moderate and weak biofilm formers constituted 46% and 23%, respectively. Overall, ciprofloxacin, levofloxacin, and cefepime showed inhibitory effects on P. aeruginosa biofilms. Antibiotics in combination showed strong synergistic effects (ciprofloxacin and cefepime), while gentamicin and cefepime resulted in complete eradication of P. aeruginosa biofilm. Conclusion We confirm strong synergistic effects of gentamicin and cefepime that completely eradicated P. aeruginosa biofilm. We further confirm inhibitory effects of ciprofloxacin, levofloxacin, and cefepime on P. aeruginosa biofilms. Hence, combination therapy can be more effective against biofilm-associated infections.
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Affiliation(s)
- Muhammad Usman
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Arooj Marcus
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Aimen Fatima
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Bushra Aslam
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Maryam Zaid
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Muska Khattak
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Sidra Bashir
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Safia Masood
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
| | - Zara Rafaque
- Department of Microbiology Hazara University Mansehra, Mansehra21120, Pakistan
| | - Javid Iqbal Dasti
- Lab of Microbial Genomics and Epidemiology, Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320, Pakistan
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Segatore B, Piccirilli A, Cherubini S, Principe L, Alloggia G, Mezzatesta ML, Salmeri M, Di Bella S, Migliavacca R, Piazza A, Meroni E, Fazii P, Visaggio D, Visca P, Cortazzo V, De Angelis G, Pompilio A, Perilli M. In Vitro Activity of Sulbactam-Durlobactam against Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates: A Multicentre Report from Italy. Antibiotics (Basel) 2022; 11:antibiotics11081136. [PMID: 36010006 PMCID: PMC9404735 DOI: 10.3390/antibiotics11081136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Bernardetta Segatore
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Alessandra Piccirilli
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Sabrina Cherubini
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Luigi Principe
- Clinical Pathology and Microbiology Unit, “S. Giovanni di Dio” Hospital, 88900 Crotone, Italy
- Correspondence:
| | - Giovanni Alloggia
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
| | - Maria Lina Mezzatesta
- Department of Biomedical and Biotechnological Sciences, Section of Microbiology, University of Catania, 95131 Catania, Italy
| | - Mario Salmeri
- Department of Biomedical and Biotechnological Sciences, Section of Microbiology, University of Catania, 95131 Catania, Italy
| | - Stefano Di Bella
- Clinical Department of Medical, Surgical and Health Sciences, University of Trieste, 34129 Trieste, Italy
| | - Roberta Migliavacca
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy
| | - Aurora Piazza
- Unit of Microbiology and Clinical Microbiology, Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy
| | - Elisa Meroni
- Clinical Microbiology and Virology Unit, “A. Manzoni” Hospital, 23900 Lecco, Italy
| | - Paolo Fazii
- Clinical Microbiology and Virology Unit, Spirito Santo Hospital, 65122 Pescara, Italy
| | - Daniela Visaggio
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
- Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Paolo Visca
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
- Santa Lucia Foundation IRCCS, 00179 Rome, Italy
| | - Venere Cortazzo
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Giulia De Angelis
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Arianna Pompilio
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
- Center of Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy
| | - Mariagrazia Perilli
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
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Yamabe K, Arakawa Y, Shoji M, Miyamoto K, Tsuchiya T, Minoura K, Akeda Y, Tomono K, Onda M. Enhancement ofAcinetobacterbaumanniibiofilm growth by cephem antibiotics via enrichment of protein and extracellular DNAin thebiofilm matrices. J Appl Microbiol 2022; 133:2002-2013. [PMID: 35818769 PMCID: PMC9539989 DOI: 10.1111/jam.15712] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/03/2022] [Accepted: 07/06/2022] [Indexed: 11/30/2022]
Abstract
AIMS To determine the effects of subinhibitory concentrations of eight cephem and carbapenem antibiotics on thebiofilm formation ofAcinetobacterbaumanniicells and examine itseffect on pre-established biofilms. METHODS AND RESULTS Effects of antibiotics on biofilm formation were assayed using microtiter plates with polystyrene peg-lids.Cefmetazole, ceftriaxone, ceftazidime, and cefpirome increased the biomass of pre-established biofilms on pegs in the range of their sub-minimum inhibitory concentrations, whereas none increased biofilm formation by planktonic cells. Carbapenems had a negative effect.The constituents of antibiotic-induced biofilms were analyzed. Ceftriaxoneor ceftazidimetreatment markedly increased the matrix constituent amounts in the biofilms (carbohydrate, 2.7-fold; protein, 8.9-12.7-fold; lipid, 3.3-3.6-fold; DNA, 9.1-12.2-fold; outer membrane vesicles, 2.7-3.8-fold; and viable cells,6.8-10.1-fold).The antibiotic-enhanced biofilmshad increased outer membrane protein A and were resistant to the anti-biofilm effect of azithromycin. CONCLUSIONS Some cephems increased the biomass of pre-established biofilms in the ranges of their sub-minimum inhibitory concentrations.The antibiotic-enhanced biofilmspossessed more virulent characteristics than normal biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY Incomplete administration of certain cephems followingbiofilm-related Ac.baumannii infectionscould adversely cause exacerbated and chronic clinical results.
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Affiliation(s)
- K Yamabe
- Department of Social and Administrative Pharmacy, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Y Arakawa
- Department of Social and Administrative Pharmacy, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - M Shoji
- Department of Social and Administrative Pharmacy, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - K Miyamoto
- Department of Microbiology and Infection Control, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - T Tsuchiya
- Department of Microbiology and Infection Control, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - K Minoura
- Joint Research Center, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Y Akeda
- National Institute of Infectious Diseases, Tokyo, Japan
| | - K Tomono
- Osaka Institute of Public Health, Osaka, Japan
| | - M Onda
- Department of Social and Administrative Pharmacy, Osaka Medical and Pharmaceutical University, Osaka, Japan
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Conrad JW, Harwood VJ. Sewage Promotes Vibrio vulnificus Growth and Alters Gene Transcription in Vibrio vulnificus CMCP6. Microbiol Spectr 2022; 10:e0191321. [PMID: 35171011 PMCID: PMC8849060 DOI: 10.1128/spectrum.01913-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus is a naturally occurring, potentially lethal pathogen found in coastal waters, fish, and shellfish. Sewage spills in coastal waters occur when infrastructure fails due to severe storms or age, and may affect bacterial populations by altering nutrient levels. This study investigated effects of sewage on clonal and natural V. vulnificus populations in microcosms. Addition of 1% sewage to estuarine water caused the density of a pure culture of V. vulnificus CMCP6 and a natural V. vulnificus population to increase significantly, by two to three orders of magnitude, whether measured by quantitative PCR (qPCR) or culture and in batch and continuous cultures. Changes in the transcription of six virulence- and survival-associated genes in response to sewage were assessed using continuous culture. Exposure to sewage affected transcription of genes that may be associated with virulence, i.e., it modulated the oxidative stress response by altering superoxide dismutase transcription, significantly increasing sodB transcription while repressing sodA. Sewage also repressed transcription of nptA, which encodes a sodium-phosphate cotransporter. Sewage had no effect on sodC transcription or the putative virulence-associated genes hupA or wza. The effects of environmentally relevant levels of sewage on V. vulnificus populations and gene transcription suggest that sewage spills that impact warm coastal waters could lead to an increased risk of V. vulnificus infections. IMPORTANCE Vibrio vulnificus infections have profound impacts such as limb amputation and death for individuals with predisposing conditions. The warming climate is contributing to rising V. vulnificus prevalence in waters that were previously too cold to support high levels of the pathogen. Climate change is also expected to increase precipitation in many regions, which puts more pressure on wastewater infrastructure and will result in more frequent sewage spills. The finding that 1% wastewater in estuarine water leads to 100 to over 1,000-fold greater V. vulnificus concentrations suggests that human exposure to oysters and estuarine water could have greater health impacts in the future. Further, wastewater had a significant effect on gene transcription and has the potential to affect virulence during the initial environment-to-host transition.
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Affiliation(s)
- James W. Conrad
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Valerie J. Harwood
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
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Abhini KN, Rajan AB, Fathimathu Zuhara K, Sebastian D. Response surface methodological optimization of L-asparaginase production from the medicinal plant endophyte Acinetobacter baumannii ZAS1. J Genet Eng Biotechnol 2022; 20:22. [PMID: 35138483 PMCID: PMC8828825 DOI: 10.1186/s43141-022-00309-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/23/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND This study targets the enhanced production of L-asparaginase, an antitumor enzyme by Acinetobacter baumannii ZAS1. This organism is an endophyte isolated from the medicinal plant Annona muricata. Plackett-Burman design (PBD) and central composite design (CCD) were used for statistical optimization of media components. RESULTS The organism exhibited 18.85 ± 0.2 U/mL enzyme activities in unoptimized media. Eight variables: L-asparagine, peptone, glucose, lactose, yeast extract, NaCl, MgSO4, and Na2HPO4 were screened by PBD. Among them, only four factors-L-asparagine, peptone, glucose, and Na2HPO4-were found to affect enzyme production significantly (p < 0.05). Furthermore, the best possible concentrations and interactive effects of the components that enhance this enzyme's output were chosen by using CCD on these selected variables. The results revealed that an optimized medium produces a higher concentration of enzymes than the unoptimized medium. After optimizing media components, the maximum L-asparaginase activity was 45.59 ± 0.36 U/mL, around the anticipated value of 45.04 ± 0.42 U/mL. After optimization of process parameters, it showed a 2.41-fold increase in the production of L-asparaginase by the endophyte Acinetobacter baumannii ZAS1. CONCLUSION The findings of this study indicated that an endophyte, Acinetobacter baumannii ZAS1 that produces L-asparaginase could be used to increase enzyme output. However, using the statistical methods Plackett-Burman design and central composite design of response surface methodology is a handy tool for optimizing media components for increased L-asparaginase synthesis.
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Affiliation(s)
- K N Abhini
- Department of Life Sciences, University of Calicut, Malappuram, Kerala, 673635, India
| | - Akhila B Rajan
- Department of Life Sciences, University of Calicut, Malappuram, Kerala, 673635, India
| | - K Fathimathu Zuhara
- Department of Life Sciences, University of Calicut, Malappuram, Kerala, 673635, India
| | - Denoj Sebastian
- Department of Life Sciences, University of Calicut, Malappuram, Kerala, 673635, India.
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Dawan J, Li Y, Lu F, He X, Ahn J. Role of Efflux Pump-Mediated Antibiotic Resistance in Quorum Sensing-Regulated Biofilm Formation by Salmonella Typhimurium. Pathogens 2022; 11:147. [PMID: 35215091 PMCID: PMC8877114 DOI: 10.3390/pathogens11020147] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
This study was designed to assess the influence of efflux pump activity on the biofilm formation in Salmonella Typhimurium. Salmonella enterica subsp. enterica serovar Typhimurium ATCC 19585 (STWT) and clinically isolated S. Typhimurium CCARM 8009 (STCI) were treated with ceftriaxone (CEF), chloramphenicol (CHL), ciprofloxacin (CIP), erythromycin (ERY), norfloxacin (NOR), and tetracycline (TET) in autoinducer-containing media in the absence and presence of phenylalanine-arginine β-naphthylamide (PAβN) to compare efflux pump activity with biofilm-forming ability. The susceptibilities of STWT and STCI were increased in the presence of PAβN. ERY+PAβN showed the highest decrease in the minimum inhibitory concentration (MIC) of ERY from 256 to 2 μg/mL against STWT and STCI. The antimicrobial activity of NOR against planktonic cells was significantly increased in the presence of PAβN, showing the lowest numbers of STWT (3.2 log CFU/cm2), and the TET+PAβN effectively inhibited the growth of STCI (5.2 log CFU/cm2). The lowest biofilm-forming abilities were observed at NOR+PAβN against STWT (biofilm-forming index, BFI < 0.41) and CEF+PAβN against STCI (BFI = 0.32). The bacteria swimming motility and relative fitness varied depending on the antibiotic and PAβN treatments. The motility diameters of STWT were significantly decreased by NOR+PAβN (6 mm) and TET+PAβN (15 mm), while the lowest motility of STCI was observed at CIP+PAβN (8 mm). The significant decrease in the relative fitness levels of STWT and STCI was observed at CIP+PAβN and NOR+PAβN. The PAβN as an efflux pump inhibitor (EPI) can improve the antimicrobial and anti-biofilm efficacy of antibiotics against S. Typhimurium. This study provides useful information for understanding the role of efflux pump activity in quorum sensing-regulated biofilm formation and also emphasizes the necessity of the discovery of novel EPIs for controlling biofilm formation by antibiotic-resistant pathogens.
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Affiliation(s)
- Jirapat Dawan
- Department of Biomedical Science, Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
| | - Yinyue Li
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Feng Lu
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Xinlong He
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou 225001, China; (Y.L.); (F.L.); (X.H.)
| | - Juhee Ahn
- Department of Biomedical Science, Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Gangwon, Korea;
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Sharma S, Das A, Banerjee T, Barman H, Yadav G, Kumar A. Adaptations of carbapenem resistant Acinetobacter baumannii (CRAB) in the hospital environment causing sustained outbreak. J Med Microbiol 2021; 70. [PMID: 33739918 DOI: 10.1099/jmm.0.001345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Introduction. Carbapenem resistance in Acinetobacter baumannii (A. baumannii) is an emerging global threat.Gap statement. The adaptation strategies of A. baumannii for this emergence as a nosocomial pathogen has been less studied.Aim. This prospective study analysed a sustained outbreak of carbapenem resistant Acinetobacter baumannii (CRAB) in the intensive care unit (ICU) with reference to antimicrobial resistance and virulence in the colonizing and pathogenic isolates under carbapenem stress.Results. The CRAB isolates from initial and sustained outbreak were found harbouring multiple carbapenemase genes. These genes included bla OXA-23 ,bla IMP, bla VIM and bla NDM. From NICU environment three phenotypically carbapenem susceptible isolates were found carrying bla OXA-23, bla IMP, bla VIM genes. Prior imipenem therapy was one of the risk factors (P=0.0016). The outbreak was polyclonal. Under imipenem stress, outbreak isolates showed no loss of carbapenemase genes against stress free conditions (23.7±1.33 days). Biofilm formation increased with imipenem concentration, with outbreak isolates producing highest biomass. While the pathogens showed a slow growth rate on imipenem exposure, the colonisers grew rapidly (P <0.0001).Methods. Sustained outbreak of CRAB was identified in the ICU (July 2015 to December 2017). Risk factors for acquisition of CRAB was studied. A. baumannii isolates were also collected from the environments of ICU and neonatal ICU (NICU) and blood cultures of septic neonates. Isolates were characterized based on antimicrobial susceptibility, genetic profile, integrons carriage and clonality. Biofilm formation and growth kinetics were studied under varying carbapenem stress.Conclusion. Intense carbapenem exposure in the ICU facilitates persistence of CRAB by several adaptations causing sustained outbreaks.
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Affiliation(s)
- Swati Sharma
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Arghya Das
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Tuhina Banerjee
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Hiranmay Barman
- Department of Anaesthesiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Ghanshyam Yadav
- Department of Anaesthesiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Ashok Kumar
- Department of Paediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
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10
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Clinical Biofilm Ring Test ® Reveals the Potential Role of β-Lactams in the Induction of Biofilm Formation by P. aeruginosa in Cystic Fibrosis Patients. Pathogens 2020; 9:pathogens9121065. [PMID: 33352641 PMCID: PMC7766936 DOI: 10.3390/pathogens9121065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/03/2022] Open
Abstract
Biofilms are characterized by high tolerance to antimicrobials. However, conventional antibiograms are performed on planktonic microorganisms. Through the clinical Biofilm Ring Test® (cBRT), initially aimed to measure the adhesion propensity of bacteria, we discerned a variable distribution of biofilm-producer strains among P. aeruginosa samples isolated from expectorations of cystic fibrosis (CF) patients. Despite a majority of spontaneous adherent isolates, few strains remained planktonic after 5 h of incubation. Their analysis by an adapted protocol of the cBRT revealed an induction of the biofilm early formation by sub-inhibitory doses of β-lactams. Microscopic observations of bacterial cultures stained with Syto 9/Propidium Iodide (PI) confirmed the ability of antimicrobials to increase either the bacterial biomass or the biovolume occupied by induced sessile cells. Finally, the cBRT and its derivatives enabled to highlight in a few hours the potential inducer property of antibiotics on bacterial adhesion. This phenomenon should be considered carefully in the context of CF since patients are constantly under fluctuating antimicrobial treatments. To conclude, assays derived from the Biofilm Ring Test® (BRT) device, not only define efficient doses preventing biofilm formation, but could be useful for the antimicrobial selection in CF, to avoid inducer molecules of the early biofilm initiation.
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11
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Babushkina IV, Ulyanov VY, Mamonova IA, Shpinyak SP. The Effect of Azithromycin on Biofilms Formation by Pathogens of Implant-Associated Infection in Large Joints. Bull Exp Biol Med 2020; 169:798-801. [PMID: 33108560 DOI: 10.1007/s10517-020-04982-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Indexed: 11/28/2022]
Abstract
We studied the effect of subbacteriostatic azithromycin concentrations on the formation of microbial biofilms by Pseudomonas aeruginosa strains that caused implant-associated infection of large joints. Azithromycin in subinhibitory for planktonic cells concentrations 0.01-0.02 μg/ml stimulated biofilm formation by both clinical and reference P. aeruginosa strains, while in concentrations of 1 μg/ml and higher completely inhibited the growth of both reference and clinical plankton P. aeruginosa strains, but stimulated biofilm formation. Increasing azithromycin concentration to 10 μg/ml led to inhibition of P. aeruginosa biofilm growth.
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Affiliation(s)
- I V Babushkina
- Research Institute of Traumatology, Orthopedics, and Neurosurgery, V. I. Razumovsky Saratov State Medical University, Ministry of Health of the Russian Federation, Saratov, Russia.
| | - V Yu Ulyanov
- Research Institute of Traumatology, Orthopedics, and Neurosurgery, V. I. Razumovsky Saratov State Medical University, Ministry of Health of the Russian Federation, Saratov, Russia
| | - I A Mamonova
- Research Institute of Traumatology, Orthopedics, and Neurosurgery, V. I. Razumovsky Saratov State Medical University, Ministry of Health of the Russian Federation, Saratov, Russia
| | - S P Shpinyak
- Research Institute of Traumatology, Orthopedics, and Neurosurgery, V. I. Razumovsky Saratov State Medical University, Ministry of Health of the Russian Federation, Saratov, Russia
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12
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Dickstein Y, Lellouche J, Ben Dalak Amar M, Schwartz D, Nutman A, Daitch V, Yahav D, Leibovici L, Skiada A, Antoniadou A, Daikos GL, Andini R, Zampino R, Durante-Mangoni E, Mouton JW, Friberg LE, Dishon Benattar Y, Bitterman R, Neuberger A, Carmeli Y, Paul M. Treatment Outcomes of Colistin- and Carbapenem-resistant Acinetobacter baumannii Infections: An Exploratory Subgroup Analysis of a Randomized Clinical Trial. Clin Infect Dis 2020; 69:769-776. [PMID: 30462182 DOI: 10.1093/cid/ciy988] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/15/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND We evaluated the association between mortality and colistin resistance in Acinetobacter baumannii infections and the interaction with antibiotic therapy. METHODS This is a secondary analysis of a randomized controlled trial of patients with carbapenem-resistant gram-negative bacterial infections treated with colistin or colistin-meropenem combination. We evaluated patients with infection caused by carbapenem-resistant A. baumannii (CRAB) identified as colistin susceptible (CoS) at the time of treatment and compared patients in which the isolate was confirmed as CoS with those whose isolates were retrospectively identified as colistin resistant (CoR) when tested by broth microdilution (BMD). The primary outcome was 28-day mortality. RESULTS Data were available for 266 patients (214 CoS and 52 CoR isolates). Patients with CoR isolates had higher baseline functional capacity and lower rates of mechanical ventilation than patients with CoS isolates. All-cause 28-day mortality was 42.3% (22/52) among patients with CoR strains and 52.8% (113/214) among patients with CoS isolates (P = .174). After adjusting for variables associated with mortality, the mortality rate was lower among patients with CoR isolates (odds ratio [OR], 0.285 [95% confidence interval {CI}, .118-.686]). This difference was associated with treatment arm: Mortality rates among patients with CoR isolates were higher in those randomized to colistin-meropenem combination therapy compared to colistin monotherapy (OR, 3.065 [95% CI, 1.021-9.202]). CONCLUSIONS Colistin resistance determined by BMD was associated with lower mortality among patients with severe CRAB infections. Among patients with CoR isolates, colistin monotherapy was associated with a better outcome compared to colistin-meropenem combination therapy. CLINICAL TRIALS REGISTRATION NCT01732250.
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Affiliation(s)
- Yaakov Dickstein
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv
| | - Jonathan Lellouche
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv.,Molecular Epidemiology Laboratory, Tel-Aviv Sourasky Medical Center
| | - Maayan Ben Dalak Amar
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv.,Molecular Epidemiology Laboratory, Tel-Aviv Sourasky Medical Center
| | - David Schwartz
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv.,Molecular Epidemiology Laboratory, Tel-Aviv Sourasky Medical Center
| | - Amir Nutman
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv.,Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv
| | - Vered Daitch
- Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv.,Department of Medicine E, Beilinson Hospital, Petah Tikva, Israel
| | - Dafna Yahav
- Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv.,Unit of Infectious Diseases, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Leonard Leibovici
- Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv.,Department of Medicine E, Beilinson Hospital, Petah Tikva, Israel
| | - Anna Skiada
- First Department of Medicine, Laikon General Hospital, Athens, Greece.,National and Kapodistrian University of Athens, Athens, Greece
| | - Anastasia Antoniadou
- National and Kapodistrian University of Athens, Athens, Greece.,Fourth Department of Medicine, Attikon University General Hospital, Athens, Greece
| | - George L Daikos
- First Department of Medicine, Laikon General Hospital, Athens, Greece.,National and Kapodistrian University of Athens, Athens, Greece
| | - Roberto Andini
- Department of Precision Medicine, University of Campania 'L Vanvitelli' and Azienda Ospedaliera di Rilievo Nazionale dei Colli-Monaldi Hospital, Napoli, Italy
| | - Rosa Zampino
- Department of Precision Medicine, University of Campania 'L Vanvitelli' and Azienda Ospedaliera di Rilievo Nazionale dei Colli-Monaldi Hospital, Napoli, Italy
| | - Emanuele Durante-Mangoni
- Department of Precision Medicine, University of Campania 'L Vanvitelli' and Azienda Ospedaliera di Rilievo Nazionale dei Colli-Monaldi Hospital, Napoli, Italy
| | - Johan W Mouton
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Lena E Friberg
- Department of Pharmaceutical Biosciences, Uppsala University, Sweden
| | - Yael Dishon Benattar
- Institute of Infectious Diseases, Rambam Health Care Campus.,Cheryl Spencer Department of Nursing, University of Haifa
| | - Roni Bitterman
- Institute of Infectious Diseases, Rambam Health Care Campus
| | - Ami Neuberger
- Institute of Infectious Diseases, Rambam Health Care Campus
| | - Yehuda Carmeli
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel-Aviv.,Molecular Epidemiology Laboratory, Tel-Aviv Sourasky Medical Center.,Sackler Faculty of Medicine, Tel Aviv University, Ramat-Aviv
| | - Mical Paul
- Institute of Infectious Diseases, Rambam Health Care Campus.,Faculty of Medicine, Technion, Israel Institute of Technology, Haifa
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13
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Lin MF, Lin YY, Lan CY. Characterization of biofilm production in different strains of Acinetobacter baumannii and the effects of chemical compounds on biofilm formation. PeerJ 2020; 8:e9020. [PMID: 32523805 PMCID: PMC7261477 DOI: 10.7717/peerj.9020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/28/2020] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii, an important emerging pathogen of nosocomial infections, is known for its ability to form biofilms. Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, which increases the probability of nosocomial infections and outbreaks. This study was undertaken to characterize the biofilm production of different strains of A. baumannii and the effects of chemical compounds, especially antibiotics, on biofilm formation. In this study, no statistically significant relationship was observed between the ability to form a biofilm and the antimicrobial susceptibility of the A. baumannii clinical isolates. Biofilm formation caused by A. baumannii ATCC 17978 after gene knockout of two-component regulatory system gene baeR, efflux pump genes emrA/emrB and outer membrane coding gene ompA revealed that all mutant strains had less biofilm formation than the wild-type strain, which was further supported by the images from scanning electron microscopy and confocal laser scanning microscopy. The addition of amikacin, colistin, LL-37 or tannic acid decreased the biofilm formation ability of A. baumannii. In contrast, the addition of lower subinhibitory concentration tigecycline increased the biofilm formation ability of A. baumannii. Minimum biofilm eradication concentrations of amikacin, imipenem, colistin, and tigecycline were increased obviously for both wild type and multidrug resistant clinical strain A. baumannii VGH2. In conclusion, the biofilm formation ability of A. baumannii varied in different strains, involved many genes and could be influenced by many chemical compounds.
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Affiliation(s)
- Ming-Feng Lin
- Department of Medicine, National Taiwan University Hospital Chu-Tung Branch, Hsinchu County, Taiwan
| | - Yun-You Lin
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan.,Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
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14
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Adamus-Białek W, Wawszczak M, Arabski M, Majchrzak M, Gulba M, Jarych D, Parniewski P, Głuszek S. Ciprofloxacin, amoxicillin, and aminoglycosides stimulate genetic and phenotypic changes in uropathogenic Escherichia coli strains. Virulence 2020; 10:260-276. [PMID: 30938219 PMCID: PMC6527016 DOI: 10.1080/21505594.2019.1596507] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Antibiotic therapy and its consequences in bacterial and human aspects are widely investigated. Despite this, the emergence of new multidrug resistant bacteria is still a current problem. The scope of our work included the observation of changes among uropathogenic Escherichia coli strains after the treatment with a subinhibitory concentration of different antibiotics. The sensitive strains with or without virulence factors were incubated with amoxicillin, ciprofloxacin, gentamycin, or tobramycin. After each passage, the E. coli derivatives were compared to their wild types based on their susceptibility profiles, virulence genes, biofilm formations and the fingerprint profiles of PCR products amplified with using the (N)(6)(CGG)(4) primer. It turned out that antibiotics caused significant changes in the repertoire of bacterial virulence and biofilm formation, corresponding to acquired cross-resistance. The genomic changes among the studied bacteria were reflected in the changed profiles of the CGG-PCR products. In conclusion, the inappropriate application of antibiotics may cause a rapid rise of Multidrug Resistant (MDR) strains and give bacteria a chance to modulate their own pathogenicity. This phenomenon has been easily observed among uropathogenic E. coli strains and it is one of the main reasons for recurrent infections of the urinary tract.
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Affiliation(s)
- Wioletta Adamus-Białek
- a Department of Surgery and Surgical Nursery with Laboratory of Genetics, Faculty of Medicine and Health Sciences , Jan Kochanowski University , Kielce , Poland
| | - Monika Wawszczak
- a Department of Surgery and Surgical Nursery with Laboratory of Genetics, Faculty of Medicine and Health Sciences , Jan Kochanowski University , Kielce , Poland
| | - Michał Arabski
- b Department of Biochemistry & Genetics , Jan Kochanowski University , Kielce , Poland
| | - Michał Majchrzak
- a Department of Surgery and Surgical Nursery with Laboratory of Genetics, Faculty of Medicine and Health Sciences , Jan Kochanowski University , Kielce , Poland
| | - Martyna Gulba
- a Department of Surgery and Surgical Nursery with Laboratory of Genetics, Faculty of Medicine and Health Sciences , Jan Kochanowski University , Kielce , Poland
| | - Dariusz Jarych
- c Institute of Medical Biology, Polish Academy of Sciences , Łódź , Poland
| | - Paweł Parniewski
- c Institute of Medical Biology, Polish Academy of Sciences , Łódź , Poland
| | - Stanisław Głuszek
- a Department of Surgery and Surgical Nursery with Laboratory of Genetics, Faculty of Medicine and Health Sciences , Jan Kochanowski University , Kielce , Poland
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15
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Phenotypic Characterization of Rhodococcus equi Biofilm Grown In Vitro and Inhibiting and Dissolving Activity of Azithromycin/Rifampicin Treatment. Pathogens 2019; 8:pathogens8040284. [PMID: 31817114 PMCID: PMC6963269 DOI: 10.3390/pathogens8040284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/01/2019] [Accepted: 12/03/2019] [Indexed: 01/11/2023] Open
Abstract
Microbial biofilm has been implicated in a wide range of chronic infections. In spite of the fact that Rhodococcus equi is a recognized cause of chronic disease in animals and humans, few studies have focused on the sessile phenotype of R.equi. The aim of this research was to phenotypically characterize the biofilm development of R. equi and its answerability for hypo-responsiveness to macrolides and rifampicin. Biofilm formation is initiated by bacterial adhesion to the surface. In this work, the ability of R. equi to adhere to the surface of human lung epithelial cells was detected by a fluorometric adhesion test performed on 40 clinical isolates. Subsequently, the capability of R. equi to produce biofilm was investigated by colorimetric, fluorescence and scanning electron microscopy analysis, revealing a general slow growth of rhodococcal biofilm and different sessile phenotypes among field isolates, some also including filamented bacteria. Azithromycin treatment produced a higher long-term inhibition and dissolution of R. equi biofilms than rifampicin, while the two antibiotics combined boosted the anti-biofilm effect in a statistically significant manner, although this was not equally effective for all R. equi isolates. Increasing the MIC concentrations of drugs tenfold alone and in combination did not completely eradicate pre-formed R. equi biofilms, while a rifampicin-resistant isolate produced an exceptionally abundant extracellular matrix. These results have strengthened the hypothesis that biofilm production may occur as an antibiotic tolerance system in R. equi, potentially determining persistence and, eventually, chronic infection.
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16
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Eze EC, El Zowalaty ME. Combined Effects Of Low Incubation Temperature, Minimal Growth Medium, And Low Hydrodynamics Optimize Acinetobacter baumannii Biofilm Formation. Infect Drug Resist 2019; 12:3523-3536. [PMID: 31814741 PMCID: PMC6863185 DOI: 10.2147/idr.s203919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 06/19/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Biofilm formation is an important virulence factor expressed by Acinetobacter baumannii. It shields and protects microbial cells from host immune responses, antibiotics, and other anti-infectives. Its effects on Acinetobacter baumannii infection treatments notwithstanding, important environmental factors that influence its formation have not been fully investigated. METHODS Biofilm formation was assessed using the qualitative modified Congo red assay and quantitative microtiter plate methods. The combined effect of temperature, medium and shear force was determined by measuring adherence (OD570 nm) in microtiter plate after incubation at 26°C, 30°C, and 37°C when biofilm-grown cells were cultured in the presence of minimal nutrient medium (EAOB) and nutrient-rich medium (TSB) without or with agitation at 50 rpm. Antibiotics susceptibility of meropenem, imipenem, and ciprofloxacin were tested with Kirby-Bauer disc method. P<0.05 was considered statistically significant in all the tests. RESULTS A noticeable variation in adherence was observed among the isolates cultured with both media. Biofilm forming capacity of the isolates range from 0.09-0.33. The majority of the isolates had their relative biofilm-forming capacity significantly (p<0.05) higher than the positive control, Acinetobacter baumannii ATCC 19606. The biofilm biomass during growth in nutrient-rich medium (TSB) without shaking was significantly different (p<0.05; Tukey's test) among the three temperatures tested compared with when it was cultured in EAOB without shaking. A positive correlation was observed between biofilm formation and resistance to imipenem (r=0.2889; p=0.05). There was a statistically significant difference among the median of the three source groups (p<0.05) compared with the median between the source groups. CONCLUSION This observation extended further the view that A. baumannii biofilm formation is enhanced when nutrient-poor medium is used at room temperature (26°C) with or without agitation compared to growth at 37°C.
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Affiliation(s)
- Emmanuel C Eze
- Medical Microbiology and Infection Control, School of Laboratory Medicine and Medical Sciences, College of Health Science, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, University of KwaZulu-Natal, Durban4000, South Africa
- Infectious Diseases and Anti-Infective Research Group, College of Pharmacy, University of Sharjah, Sharjah27272, UAE
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17
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Gao Q, Meng X, Gu H, Chen X, Yang H, Qiao Y, Guo X. Two Phenotype-Differentiated Acinetobacter baumannii Mutants That Survived in a Meropenem Selection Display Large Differences in Their Transcription Profiles. Front Microbiol 2019; 10:2308. [PMID: 31649648 PMCID: PMC6794425 DOI: 10.3389/fmicb.2019.02308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/20/2019] [Indexed: 11/13/2022] Open
Abstract
37662RM1 and 37662RM2 are two phenotypically different, carbapenem-resistant mutants of Acinetobacter baumannii 37662 isolate following selection with meropenem (MEM) at sub-inhibitory concentrations. 37662RM2 lacks capsule synthesis and shows dramatically increased biofilm formation, while 37662RM1 shows merely impaired capsule synthesis. Here we report that 37662RM1 and RM2 have transcription profiles that are different from those of their starting strain, 37662WT. There were far more differentially expressed genes in 37662RM2 than in 37662RM1. The capsule polysaccharide (CPS) synthesis-required genes (itrA2, gtr5, psaA, psaB, psaC, psaD, psaE, psaF, kpsS2, wzx, wzy, wza, wzb, and wzc) showed reduced transcription levels in 37662RM2, which may at least partially explain the loss of capsule synthesis. The csu operon genes responsible for pili assembly and their regulator genes bfmR-bfmS were over-expressed in 37662RM2. This result together with the established critical roles of these genes in biofilm formation provide solid evidence that up-regulation of csu and bfmR-bfmS should be considered responsible for the enhanced biofilm formation in 37662RM2. ISAba1 was found to insert into the intergenic region between the csu operon and the acrR gene and should be responsible for the significant up-regulation of acrR, which was proposed to be associated with biofilm formation. Genome sequencing revealed that the ISAba1 upstream bla OXA- 508 (a new member of bla OXA- 51-like) and acrR were duplicated, suggesting a replicative transposition event. Altogether, the phenotype divergence driven by MEM selection mainly occurs at the RNA level and the transposition of ISAba1 plays an important role in modulating gene expression to adapt to the environment.
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Affiliation(s)
- Qianqian Gao
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiaobin Meng
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Hanfu Gu
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Xueqin Chen
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Huaqing Yang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yangyang Qiao
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xuemin Guo
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China.,Key Laboratory of Tropical Disease Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
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18
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Gaiarsa S, Bitar I, Comandatore F, Corbella M, Piazza A, Scaltriti E, Villa L, Postiglione U, Marone P, Nucleo E, Pongolini S, Migliavacca R, Sassera D. Can Insertion Sequences Proliferation Influence Genomic Plasticity? Comparative Analysis of Acinetobacter baumannii Sequence Type 78, a Persistent Clone in Italian Hospitals. Front Microbiol 2019; 10:2080. [PMID: 31572316 PMCID: PMC6751323 DOI: 10.3389/fmicb.2019.02080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/23/2019] [Indexed: 01/23/2023] Open
Abstract
Acinetobacter baumannii is a known opportunistic pathogen, dangerous for public health mostly due to its ability to rapidly acquire antibiotic-resistance traits. Its genome was described as characterized by remarkable plasticity, with a high frequency of homologous recombinations and proliferation of Insertion Sequences (IS). The SMAL pulsotype is an A. baumannii strain currently isolated only in Italy, characterized by a low incidence and a high persistence over the years. In this present work, we have conducted a comparative genomic analysis on this clone. The genome of 15 SMAL isolates was obtained and characterized in comparison with 24 other assemblies of evolutionary related isolates. The phylogeny highlighted the presence of a monophyletic clade (named ST78A), which includes the SMAL isolates. ST78A isolates have a low rate of homologous recombination and low gene content variability when compared to two related clades (ST78B and ST49) and to the most common A. baumannii variants worldwide (International Clones I and II). Remarkably, genomes in the ST78A clade present a high number of IS, including classes mostly absent in the other related genomes. Among these IS, one copy of IS66 was found to interrupt the gene comEC/rec2, involved in the acquisition of exogenous DNA. The genomic characterization of SMAL isolates shed light on the surprisingly low genomic plasticity and the high IS proliferation present in this strain. The interruption of the gene comEC/rec2 by an IS in the SMAL genomes brought us to formulate an evolutionary hypothesis according to which the proliferation of IS is slowing the acquisition of exogenous DNA, thus limiting genome plasticity. Such genomic architecture could explain the epidemiological behavior of high persistence and low incidence of the clone and provides an interesting framework to compare ST78 with the highly epidemic International Clones, characterized by high genomic plasticity.
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Affiliation(s)
- Stefano Gaiarsa
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Ibrahim Bitar
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Francesco Comandatore
- Pediatric Clinical Research Center, Dipartimento di Scienze Biomediche e Cliniche “Luigi Sacco”, Università degli Studi di Milano, Milan, Italy
| | - Marta Corbella
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Servizio di Epidemiologia Clinica e Biometria, Direzione Scientifica, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Aurora Piazza
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
- Pediatric Clinical Research Center, Dipartimento di Scienze Biomediche e Cliniche “Luigi Sacco”, Università degli Studi di Milano, Milan, Italy
| | - Erika Scaltriti
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Parma, Italy
| | - Laura Villa
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanitá, Rome, Italy
| | - Umberto Postiglione
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, Università degli Studi di Pavia, Pavia, Italy
| | - Piero Marone
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Elisabetta Nucleo
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Stefano Pongolini
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Parma, Italy
| | - Roberta Migliavacca
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Davide Sassera
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, Università degli Studi di Pavia, Pavia, Italy
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19
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Eze EC, Chenia HY, El Zowalaty ME. Acinetobacter baumannii biofilms: effects of physicochemical factors, virulence, antibiotic resistance determinants, gene regulation, and future antimicrobial treatments. Infect Drug Resist 2018; 11:2277-2299. [PMID: 30532562 PMCID: PMC6245380 DOI: 10.2147/idr.s169894] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections due to its increased antibiotic resistance and virulence. The ability of A. baumannii to form biofilms contributes to its survival in adverse environmental conditions including hospital environments and medical devices. A. baumannii has undoubtedly propelled the interest of biomedical researchers due to its broad range of associated infections especially in hospital intensive care units. The interplay among microbial physicochemistry, alterations in the phenotype and genotypic determinants, and the impact of existing ecological niche and the chemistry of antimicrobial agents has led to enhanced biofilm formation resulting in limited access of drugs to their specific targets. Understanding the triggers to biofilm formation is a step towards limiting and containing biofilm-associated infections and development of biofilm-specific countermeasures. The present review therefore focused on explaining the impact of environmental factors, antimicrobial resistance, gene alteration and regulation, and the prevailing microbial ecology in A. baumannii biofilm formation and gives insights into prospective anti-infective treatments.
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Affiliation(s)
- Emmanuel C Eze
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
| | - Hafizah Y Chenia
- Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Mohamed E El Zowalaty
- Virology and Microbiology Research Group, School of Health Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa,
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20
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Novović K, Mihajlović S, Dinić M, Malešević M, Miljković M, Kojić M, Jovčić B. Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells. PLoS One 2018; 13:e0201608. [PMID: 30071077 PMCID: PMC6072067 DOI: 10.1371/journal.pone.0201608] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/18/2018] [Indexed: 01/11/2023] Open
Abstract
Acinetobacter baumannii has been recognized as one of the most challeging pathogens in clinical settings worldwide. Outer membrane porins play a significant role in Acinetobacter antibiotic resistance and virulence. A. baumannii carbapenem resistance and virulence factor porin Omp33-36 was the subject of this study. We investigated the omp33-36 gene transcriptional response in the growth phase, its response to carbapenems, and the effect of contact with host cells. Additionally, the cytotoxic effect of A. baumannii towards keratinocytes was assessed, as well as correlation between omp33-36 gene transcription and cytotoxicity. Further, Acinetobacter spp. Omp33-36 was classified and its characteristics relevant for vaccine candidature were determined. The level of the omp33-36 gene transcription varied between growth phases, but a common pattern could not be established among different strains. Treatment with subinhibitory concentrations of carbapenems decreased, while contact with keratinocytes increased omp33-36 expression in the analysed A. baumannii strains. Variations in omp33-36 mRNA levels did not correlate with cytotoxicity levels. Decrease of omp33-36 mRNA during treatment with subinhibitory concentrations of carbapenems, indicated the importance of transcriptional changes in reversible resistance to carbapenems due to the absence of Omp33-36. The transcription of omp33-36 increased after contact with keratinocytes, indicating the important role of de novo transcription during the initial phase of A. baumannii infection. Primary structural analysis of Acinetobacter spp. Omp33-36 revealed three distinct groups (among four A. baumannii variants). Although we have shown that Omp33-36 was highly polymorphic, we propose a potential antigen (PLAEAAFL motif) for vaccine development. According to PROVEAN analysis, the highly polymorphic structure of Omp33-36 porin should not influence its function significantly.
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Affiliation(s)
- Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Sanja Mihajlović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Miroslav Dinić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milka Malešević
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Marija Miljković
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
- * E-mail:
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21
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Ranieri MR, Whitchurch CB, Burrows LL. Mechanisms of biofilm stimulation by subinhibitory concentrations of antimicrobials. Curr Opin Microbiol 2018; 45:164-169. [PMID: 30053750 DOI: 10.1016/j.mib.2018.07.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/11/2018] [Indexed: 10/28/2022]
Abstract
Biofilms are a typical mode of growth for most microorganisms and provide them with a variety of survival benefits. Biofilms can pose medical and industrial challenges due to their increased tolerance of antimicrobials and disinfectants. Exposure of bacteria to subinhibitory concentrations of those compounds can further exacerbate the problem, as they provoke physiological changes that lead to increased biofilm production and potential therapeutic failure. The protected niche of a biofilm provides conditions that promote selection for persisters and resistant mutants. In this review we discuss our current understanding of the mechanisms underlying biofilm stimulation in response to subinhibitory antimicrobials, and how we might exploit this 'anti-antibiotic' phenotype to treat biofilm-related infections and discover new compounds.
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Affiliation(s)
- Michael Rm Ranieri
- Dept. of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Canada
| | | | - Lori L Burrows
- Dept. of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Canada.
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22
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Mosharaf MK, Tanvir MZH, Haque MM, Haque MA, Khan MAA, Molla AH, Alam MZ, Islam MS, Talukder MR. Metal-Adapted Bacteria Isolated From Wastewaters Produce Biofilms by Expressing Proteinaceous Curli Fimbriae and Cellulose Nanofibers. Front Microbiol 2018; 9:1334. [PMID: 29988579 PMCID: PMC6026672 DOI: 10.3389/fmicb.2018.01334] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/31/2018] [Indexed: 11/13/2022] Open
Abstract
Bacterial biofilm plays a pivotal role in bioremediation of heavy metals from wastewaters. In this study, we isolated and identified different biofilm producing bacteria from wastewaters. We also characterized the biofilm matrix [i.e., extracellular polymeric substances (EPS)] produced by different bacteria. Out of 40 isolates from different wastewaters, only 11 (27.5%) isolates (static condition at 28°C) and 9 (22.5%) isolates (agitate and static conditions at 28 and 37°C) produced air–liquid (AL) and solid–air–liquid (SAL) biofilms, respectively, only on salt-optimized broth plus 2% glycerol (SOBG) but not in other media tested. Biomass biofilms and bacteria coupled with AL biofilms were significantly (P ≤ 0.001) varied in these isolates. Escherichia coli (isolate ENSD101 and ENST501), Enterobacter asburiae (ENSD102), Enterobacter ludwigii (ENSH201), Pseudomonas fluorescens (ENSH202 and ENSG304), uncultured Vitreoscilla sp. (ENSG301 and ENSG305), Acinetobacter lwoffii (ENSG302), Klebsiella pneumoniae (ENSG303), and Bacillus thuringiensis (ENSW401) were identified based on 16S rRNA gene sequencing. Scanning electron microscope (SEM) images revealed that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, A. lwoffii ENSG302, and K. pneumoniae ENSG303 are highly fibrous, compact, and nicely interlinked as compared to the biofilm developed by E. ludwigii ENSH201 and B. thuringiensis ENSW401. X-ray diffraction (XRD) results indicated that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 are non-crystalline amorphous nature. Fourier transform infrared (FTIR) spectroscopy showed that proteins and polysaccharides are the main components of the biofilms. Congo red binding results suggested that all these bacteria produced proteinaceous curli fimbriae and cellulose-rich polysaccharide. Production of cellulose was also confirmed by Calcofluor binding- and spectrophotometric assays. E. asburiae ENSD102, Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 were tested for their abilities to form the biofilms exposure to 0 to 2000 mg/L of copper sulfate (for Cu), zinc sulfate (for Zn), lead nitrate (for Pb), nickel chloride (for Ni), and potassium dichromate (for Cr), several concentrations of these metals activated the biofilm formation. The polysaccharides is known to sequester the heavy metals thus, these bacteria might be applied to remove the heavy metals from wastewater.
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Affiliation(s)
- M K Mosharaf
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M Z H Tanvir
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M M Haque
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M A Haque
- Department of Agro-Processing, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M A A Khan
- Department of Plant Pathology, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - A H Molla
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - Mohammad Z Alam
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | - M S Islam
- Bangladesh Jute Research Institute, Dhaka, Bangladesh
| | - M R Talukder
- Department of Environmental Science, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
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23
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Li YH, Zhou YH, Ren YZ, Xu CG, Liu X, Liu B, Chen JQ, Ding WY, Zhao YL, Yang YB, Wang S, Liu D. Inhibition of Streptococcus suis Adhesion and Biofilm Formation in Vitro by Water Extracts of Rhizoma Coptidis. Front Pharmacol 2018; 9:371. [PMID: 29713285 PMCID: PMC5911698 DOI: 10.3389/fphar.2018.00371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/29/2018] [Indexed: 12/12/2022] Open
Abstract
Streptococcus suis is difficult to treat and responsible for various infections in humans and pigs. It can also form biofilms and induce persistent infections. Rhizoma Coptidis is a medicinal plant widely used in Traditional Chinese Medicine. Although the inhibitory effects of Rhizoma Coptidis on biofilm formation have been investigated in several studies, the ability of Rhizoma Coptidis to inhibit S. suis biofilm formation and the underlying mechanisms have not yet been reported. In this study, we showed that sub-minimal inhibitory concentrations (25 and 50 μg mL-1) of water extracts of Rhizoma Coptidis (Coptis deltoidea C.Y.Cheng & P.K.Hsiao, obtained from Sichuan Province) were sufficient to inhibit biofilm formation, as shown in the tissue culture plate (TCP) method and scanning electron microscopy. Real-time PCR and iTRAQ were used to measure gene and protein expression in S. suis. Sub-minimum inhibitory concentrations (25 and 50 μg mL-1) of Rhizoma Coptidis water extracts inhibited S. suis adhesion significantly in an anti-adherence assay. Some genes, such as gapdh, sly, and mrp, and proteins, such as antigen-like protein, CPS16V, and methyltransferase H, involved in adhesion were significantly modulated in cells treated with 50 μg mL-1 of Rhizoma Coptidis water extracts compared to untreated cells. The results from this study suggest that compounds in Rhizoma Coptidis water extracts play an important role in inhibiting adhesion of S. suis cells and, therefore, biofilm formation.
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Affiliation(s)
- Yan-Hua Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yong-Hui Zhou
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yong-Zhi Ren
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Chang-Geng Xu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Xin Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Bing Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Jian-Qing Chen
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Wen-Ya Ding
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yu-Lin Zhao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yan-Bei Yang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Shuai Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Di Liu
- Heilongjiang Academy of Agricultural Sciences, Harbin, China
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24
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Zhou YH, Xu CG, Yang YB, Xing XX, Liu X, Qu QW, Ding WY, Bello-Onaghise G, Li YH. Histidine Metabolism and IGPD Play a Key Role in Cefquinome Inhibiting Biofilm Formation of Staphylococcus xylosus. Front Microbiol 2018; 9:665. [PMID: 29675012 PMCID: PMC5896262 DOI: 10.3389/fmicb.2018.00665] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/21/2018] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus xylosus (S. xylosus) is an AT-rich and coagulase-negative Staphylococcus (CNS). It is normally regarded as non-pathogenic, however, recent studies have demonstrated that it is related to human opportunistic infections and bovine mastitis. In addition, S. xylosus strains have the ability to form biofilm. Biofilms are also involved in chronic infections and antibiotic resistance, there are only a few reports about cefquinome inhibiting S. xylosus biofilm formation and the protein targets of cefquinome. In our study, we found that sub-MICs of cefquinome were sufficient to inhibit biofilm formation. To investigate the potential protein targets of cefquinome, we used iTRAQ for the analyses of cells at two different conditions: 1/2-MIC (0.125 μg/mL) cefquinome treatment and no treatment. Using iTRAQ technique and KEGG database analysis, we found that proteins differently expression in histidine metabolism pathway may play a role in the process by which 1/2-MIC (0.125 μg/mL) cefquinome inhibits S. xylosus biofilm formation. Interestingly, we found a sharply down-regulated enzyme [A0A068E9J3 imidazoleglycerol-phosphate dehydratase (IGPD)] involved in histidine metabolism pathway in cefquinome-treated cells. We demonstrated the important role of IGPD in sub-MICs cefquinome inhibiting biofilm formation of S. xylosus by gene (hisB) knockout, IGPD enzyme activity and histidine content assays. Thus, our data sheds light on important role of histidine metabolism in S. xylosus biofilm formation; especially, IGPD involved in histidine metabolism might play a crucial role in sub-MICs cefquinome inhibition of biofilm formation of S. xylosus, and we propose IGPD as an attractive protein target of cefquinome.
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Affiliation(s)
- Yong-Hui Zhou
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Chang-Geng Xu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yan-Bei Yang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Xiao-Xu Xing
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Xin Liu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Qian-Wei Qu
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Wen-Ya Ding
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - God'spower Bello-Onaghise
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
| | - Yan-Hua Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Heilongjiang Key Laboratory for Animal Disease Control and Pharmaceutical Development, Harbin, China
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25
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Sub-minimum inhibitory concentrations of colistin and polymyxin B promote Acinetobacter baumannii biofilm formation. PLoS One 2018; 13:e0194556. [PMID: 29554105 PMCID: PMC5858813 DOI: 10.1371/journal.pone.0194556] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 03/06/2018] [Indexed: 01/29/2023] Open
Abstract
We investigated the numbers of planktonic and biofilm cells and the expression levels of genes encoding efflux pumps and biofilm-related proteins in 10 clinical isolates of multi-drug resistant Acinetobacter baumannii (MDRA) as well as in its standard strain ATCC 19606 in the presence of colistin (CST), polymyxin B (PMB), minomycin (MIN), and tigecycline (TGC) at their respective sub-MICs. The number of planktonic and biofilm cells of ATCC 19606 decreased in the presence of all aforementioned antibiotics in a dose-dependent manner. Cell number also decreased in two representative MDRA strains, R2 and R3, in the presence of MIN and TGC in a dose-dependent manner. In contrast, the number of biofilm cells in these two strains increased in the presence of CST, while they increased significantly in the presence of PMB in R2 only. Pearson correlation analysis revealed that the number of biofilm cells was positively and significantly correlated with the mRNA levels of genes encoding efflux pumps (adeB and adeG) and autoinducer synthase (abaI) in strain R2 and adeB, adeG, adeJ, poly-acetyl-glucosamine-porin (pgaA), and abaI in strain R3 in the presence of CST. It was positively and significantly correlated with the mRNA levels of genes encoding adeB in strain R2 and an outer membrane protein A (ompA) and biofilm-associated protein (bap) in strain R3 in the presence of PMB. These results provide valuable insights into the biofilm formation potency of clinical isolates of MDRA that depends on efflux pumps and biofilm-related genes and its regulation by antibiotics.
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26
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Abstract
Surface-attached colonies of bacteria known as biofilms play a major role in the pathogenesis of device-related infections. Biofilm colonies are notorious for their resistance to suprainhibitory concentrations of antibiotics. Numerous studies have shown that subminimal inhibitory concentrations of some antibiotics can act as agonists of bacterial biofilm formation in vitro, a process that may have clinical relevance. This article reviews studies demonstrating that low-dose antibiotics induce bacterial biofilm formation. These studies have provided important information about the regulation of biofilm formation and the signaling pathways involved in global gene regulation in response to cell stressors. It is still unclear whether antibiotic-induced biofilm formation contributes to the inconsistent success of antimicrobial therapy for device infections.
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27
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Parai D, Banerjee M, Dey P, Chakraborty A, Islam E, Mukherjee SK. Effect of reserpine on Pseudomonas aeruginosa quorum sensing mediated virulence factors and biofilm formation. BIOFOULING 2018; 34:320-334. [PMID: 29482361 DOI: 10.1080/08927014.2018.1437910] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
This study aimed to evaluate the effect of reserpine, a plant-derived indole-alkaloid, against Pseudomonas aeruginosa PAO1 biofilms. The anti-biofilm activity of reserpine was evaluated by crystal violet staining, MTT assay, confocal laser scanning microscopy and scanning electron microscopy. Reserpine effects were also assessed by qRT-PCR of quorum sensing (QS)-regulated genes and biochemical quantification of the QS-mediated virulence factors pyocyanin, rhamnolipids, proteases and elastases. Reserpine reduced biofilm formation, cell motility, virulence factor production, and QS-controlled gene expression. Additionally, molecular docking analysis for AHL synthase LasI and QS transcriptional regulators LasR/MvfR revealed a plausible molecular mechanisms of reserpine QS inhibition. These findings provide insights into the underlying mode of action of reserpine, which may be useful in the development of new drugs against biofilm-related infections.
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Affiliation(s)
- Debaprasad Parai
- a Department of Microbiology , University of Kalyani , Kalyani , India
| | - Malabika Banerjee
- a Department of Microbiology , University of Kalyani , Kalyani , India
| | - Pia Dey
- a Department of Microbiology , University of Kalyani , Kalyani , India
| | | | - Ekramul Islam
- a Department of Microbiology , University of Kalyani , Kalyani , India
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28
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Bogdan M, Drenjancevic D, Harsanji Drenjancevic I, Bedenic B, Zujic Atalic V, Talapko J, Vukovic D. In vitro effect of subminimal inhibitory concentrations of antibiotics on the biofilm formation ability of Acinetobacter baumannii clinical isolates. J Chemother 2017; 30:16-24. [PMID: 28956494 DOI: 10.1080/1120009x.2017.1378835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The ability of A cinetobacter baumannii strains to form biofilm is one of the most important virulence factor which enables bacterial survival in a harsh environment and decreases antibiotic concentration as well. Subminimal inhibitory concentrations (subMICs) of antibiotics may change bacterial ultrastructure or have an influence on some different molecular mechanisms resulting in morphological or physiological changes in bacteria itself. The aim of this study was to determine effects of 1/2, 1/4, 1/8 and 1/16 minimal inhibitory concentrationsof imipenem, ampicillin-sulbactam, azithromycin, rifampicin and colistin on biofilm formation ability of 22 biofilm non-producing and 46 biofilm producing A. baumannii strains (30 weak producing strains and 16 moderate producing strains). Results of this study indicate that 1/2-1/16 MICs of imipenem, azithromycin, and rifampicin can reduce bacterial biofilm formation ability in moderate producing strains (p < 0.05), whereas 1/16 MIC of imipenem and 1/4-1/8 MICs of rifampicin reduce the biofilm formation in weak producing strains (p < 0.05). Statisticaly significant effect was detected among biofilm non-producing strains after their exposure to 1/16 MIC of azithromycin (p = 0.039). SubMICs of ampicillin-sulbactam and colistin did not have any significant effect on biofilm formation among tested A. baumannii strains.
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Affiliation(s)
- Maja Bogdan
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Domagoj Drenjancevic
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia.,c Department of Transfusion Medicine , Osijek University Hospital , Osijek , Croatia
| | - Ivana Harsanji Drenjancevic
- d Department of Anesthesiology, Reanimatology and Intensive Medicine , Osijek University Hospital , Osijek , Croatia.,e Faculty of Medicine, Department of Anesthesiology, Reanimatology and Intensive Medicine , University of Osijek , Osijek , Croatia
| | - Branka Bedenic
- f Department of Clinical and Molecular Microbiology , University Hospital Center Zagreb , Zagreb , Croatia.,g Department of Microbiology and Parasitology , School of Medicine, University of Zagreb , Zagreb , Croatia
| | - Vlasta Zujic Atalic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia.,b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Jasminka Talapko
- b Faculty of Medicine, Department of Microbiology and Parasitology , University of Osijek , Osijek , Croatia
| | - Dubravka Vukovic
- a Microbiology Service , Institute of Public Health Osijek-Baranja County , Osijek , Croatia
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29
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Analysis of Shigella flexneri Resistance, Biofilm Formation, and Transcriptional Profile in Response to Bile Salts. Infect Immun 2017; 85:IAI.01067-16. [PMID: 28348056 DOI: 10.1128/iai.01067-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 03/23/2017] [Indexed: 01/07/2023] Open
Abstract
The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge regarding how the bacteria survive, transit, and regulate gene expression prior to infection remain. In this study, we define mechanisms of resistance to bile salts and build on previous research highlighting induced virulence in Shigella flexneri strain 2457T following exposure to bile salts. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations. Interestingly, extended periods of exposure to bile salts led to biofilm formation, a conserved phenotype that we observed among members of the Enterobacteriaceae Characterization of S. flexneri 2457T biofilms determined that both bile salts and glucose were required for formation, dispersion was dependent upon bile salts depletion, and recovered bacteria displayed induced adherence to HT-29 cells. RNA-sequencing analysis verified an important bile salt transcriptional profile in S. flexneri 2457T, including induced drug resistance and virulence gene expression. Finally, functional mutagenesis identified the importance of the AcrAB efflux pump and lipopolysaccharide O-antigen synthesis for bile salt resistance. Our data demonstrate that S. flexneri 2457T employs multiple mechanisms to survive exposure to bile salts, which may have important implications for multidrug resistance. Furthermore, our work confirms that bile salts are important physiological signals to activate S. flexneri 2457T virulence. This work provides insights into how exposure to bile likely regulates Shigella survival and virulence during host transit and subsequent colonic infection.
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Bayramov DF, Neff JA. Beyond conventional antibiotics - New directions for combination products to combat biofilm. Adv Drug Deliv Rev 2017; 112:48-60. [PMID: 27496704 DOI: 10.1016/j.addr.2016.07.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/10/2016] [Accepted: 07/26/2016] [Indexed: 12/17/2022]
Abstract
Medical device related infections are a significant and growing source of morbidity and mortality. Biofilm formation is a common feature of medical device infections that is not effectively prevented or treated by systemic antibiotics. Antimicrobial medical device combination products provide a pathway for local delivery of antimicrobial therapeutics with the ability to achieve high local concentrations while minimizing systemic side effects. In this review, we present considerations for the design of local antimicrobial delivery systems, which can be facilitated by modeling local pharmacokinetics in the context of the target device application. In addition to the need for local delivery, a critical barrier to progress in the field is the need to incorporate agents effective against biofilm. This article aims to review key properties of antimicrobial peptides that make them well suited to meet the demands of the next generation of antimicrobial medical devices, including broad spectrum activity, rapid and biocidal mechanisms of action, and efficacy against biofilm.
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Chen H, Cao J, Zhou C, Liu H, Zhang X, Zhou T. Biofilm Formation Restrained by Subinhibitory Concentrations of Tigecyclin in Acinetobacter baumannii Is Associated with Downregulation of Efflux Pumps. Chemotherapy 2016; 62:128-133. [PMID: 27816975 DOI: 10.1159/000450537] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/21/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Tigecycline, one of the few therapeutic options against multidrug-resistant Acinetobacter baumannii, reaches subinhibitory serum concentrations only with cautious clinical dosing and pharmacokinetics. Subinhibitory concentrations of tigecycline might induce an A. baumannii biofilm. METHODS Biofilm formation was assessed via the crystal violet staining method. We further analyzed the main biofilm components with NaIO4, proteinase K, and DNase. Real-time RT-PCR was applied for quantitative detection of biofilm potential-associated genes. RESULTS In this study, A. baumannii proved to be a strong biofilm producer, and we found that proteins and extracellular DNA are crucial components of the A. baumannii biofilm. Quantitative real-time RT-PCR revealed positive correlations between biofilm formation restrained by subinhibitory concentrations of tigecycline and the expression of biofilm potential-associated genes, especially the AdeFGH efflux pump gene. CONCLUSION Our results suggest that downregulation of efflux pumps, especially the AdeFGH efflux pump, is probably responsible for the decline in biofilm formation in A. baumannii treated with subinhibitory concentrations of tigecyclin.
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Affiliation(s)
- Huale Chen
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Kaushik S, Sarma MK, Thungon PD, Santhosh M, Goswami P. Thin films of silk fibroin and its blend with chitosan strongly promote biofilm growth of Synechococcus sp. BDU 140432. J Colloid Interface Sci 2016; 479:251-259. [DOI: 10.1016/j.jcis.2016.06.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/27/2016] [Accepted: 06/27/2016] [Indexed: 01/08/2023]
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Imipenem Treatment Induces Expression of Important Genes and Phenotypes in a Resistant Acinetobacter baumannii Isolate. Antimicrob Agents Chemother 2015; 60:1370-6. [PMID: 26666943 DOI: 10.1128/aac.01696-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 12/05/2015] [Indexed: 12/28/2022] Open
Abstract
Acinetobacter baumannii has emerged as a notorious multidrug-resistant pathogen, and development of novel control measures is of the utmost importance. Understanding the factors that play a role in drug resistance may contribute to the identification of novel therapeutic targets. Pili are essential for A. baumannii adherence to and biofilm formation on abiotic surfaces as well as virulence. In the present study, we found that biofilm formation was significantly induced in an imipenem-resistant (Imp(r)) strain treated with a subinhibitory concentration of antibiotic compared to that in an untreated control and an imipenem-susceptible (Imp(s)) isolate. Using microarray and quantitative PCR analyses, we observed that several genes responsible for the synthesis of type IV pili were significantly upregulated in the Imp(r) but not in the Imp(s) isolate. Notably, this finding is corroborated by an increase in the motility of the Imp(r) strain. Our results suggest that the ability to overproduce colonization factors in response to imipenem treatment confers biological advantage to A. baumannii and may contribute to clinical success.
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Yang YB, Wang S, Wang C, Huang QY, Bai JW, Chen JQ, Chen XY, Li YH. Emodin affects biofilm formation and expression of virulence factors in Streptococcus suis ATCC700794. Arch Microbiol 2015; 197:1173-80. [PMID: 26446827 DOI: 10.1007/s00203-015-1158-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 10/23/2022]
Abstract
Streptococcus suis (S. suis) is a swine pathogen and also a zoonotic agent. In this study, the effects of subinhibitory concentrations (sub-MICs) of emodin on biofilm formation by S. suis ATCC700794 were evaluated. As quantified by crystal violet staining, biofilm formation by S. suis ATCC700794 was dose-dependently decreased after growth with 1/2 MIC, 1/4 MIC, or 1/8 MIC of emodin. By scanning electron microscopy, the structural architecture of the S. suis ATCC700794 biofilms was examined following growth in culture medium supplemented with 1/2 MIC, 1/4 MIC, 1/8 MIC, or 1/16 MIC of emodin. Scanning electron microscopy analysis revealed the potential effect of emodin on biofilm formation by S. suis ATCC700794. The expression of luxS gene and virulence genes in S. suis ATCC700794 was investigated by quantitative RT-PCR. It was found that sub-MICs of emodin significantly decreased the expression of gapdh, sly, fbps, ef, and luxS. However, it was found that sub-MICs of emodin significantly increased the expression of cps2J, mrp, and gdh. These findings showed that sub-MICs of emodin could cause the difference in the expression level of the virulence genes.
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Affiliation(s)
- Yan-Bei Yang
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China.
| | - Shuai Wang
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Chang Wang
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Quan-Yong Huang
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Jing-Wen Bai
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Jian-Qing Chen
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Xue-Ying Chen
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China
| | - Yan-Hua Li
- College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Xiangfang, Harbin, 150030, Heilongjiang, People's Republic of China.
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Hathroubi S, Fontaine-Gosselin SÈ, Tremblay YDN, Labrie J, Jacques M. Sub-inhibitory concentrations of penicillin G induce biofilm formation by field isolates of Actinobacillus pleuropneumoniae. Vet Microbiol 2015; 179:277-86. [PMID: 26130517 DOI: 10.1016/j.vetmic.2015.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 06/05/2015] [Accepted: 06/17/2015] [Indexed: 11/28/2022]
Abstract
Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bioavailability. This may expose A. pleuropneumoniae to sub-inhibitory concentrations of penicillin G when the antibiotic is administered orally. Our goal was to evaluate the effect of sub-minimum inhibitory concentration (MIC) of penicillin G on the biofilm formation of A. pleuropneumoniae. Biofilm production of 13 field isolates from serotypes 1, 5a, 7 and 15 was tested in the presence of sub-MIC of penicillin G using a polystyrene microtiter plate assay. Using microscopy techniques and enzymatic digestion, biofilm architecture and composition were also characterized after exposure to sub-MIC of penicillin G. Sub-MIC of penicillin G significantly induced biofilm formation of nine isolates. The penicillin G-induced biofilms contained more poly-N-acetyl-D-glucosamine (PGA), extracellular DNA and proteins when compared to control biofilms grown without penicillin G. Additionally, penicillin G-induced biofilms were sensitive to DNase which was not observed with the untreated controls. Furthermore, sub-MIC of penicillin G up-regulated the expression of pgaA, which encodes a protein involved in PGA synthesis, and the genes encoding the envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs of penicillin G significantly induce biofilm formation and this is likely the result of a cell envelope stress sensed by the CpxRA system resulting in an increased production of PGA and other matrix components.
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Affiliation(s)
- S Hathroubi
- Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, C. P. 5000, St-Hyacinthe, Québec J2S 7C6, Canada
| | - S-È Fontaine-Gosselin
- Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, C. P. 5000, St-Hyacinthe, Québec J2S 7C6, Canada
| | - Y D N Tremblay
- Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, C. P. 5000, St-Hyacinthe, Québec J2S 7C6, Canada
| | - J Labrie
- Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, C. P. 5000, St-Hyacinthe, Québec J2S 7C6, Canada
| | - M Jacques
- Groupe de recherche sur les maladies infectieuses du porc, Faculté de médecine vétérinaire, Université de Montréal, C. P. 5000, St-Hyacinthe, Québec J2S 7C6, Canada.
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Gannesen AV, Zhurina MV, Veselova MA, Khmel’ IA, Plakunov VK. Regulation of biofilm formation by Pseudomonas chlororaphis in an in vitro system. Microbiology (Reading) 2015. [DOI: 10.1134/s0026261715030042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Biofilm Formation Caused by Clinical Acinetobacter baumannii Isolates Is Associated with Overexpression of the AdeFGH Efflux Pump. Antimicrob Agents Chemother 2015; 59:4817-25. [PMID: 26033730 DOI: 10.1128/aac.00877-15] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/25/2015] [Indexed: 01/05/2023] Open
Abstract
Chronic wound infections are associated with biofilm formation, which in turn has been correlated with drug resistance. However, the mechanism by which bacteria form biofilms in clinical environments is not clearly understood. This study was designed to investigate the biofilm formation potency of Acinetobacter baumannii and the potential association of biofilm formation with genes encoding efflux pumps, quorum-sensing regulators, and outer membrane proteins. A total of 48 clinically isolated A. baumannii strains, identified by enterobacterial repetitive intergenic consensus (ERIC)-PCR as types A-II, A-III, and A-IV, were analyzed. Three representative strains, which were designated A. baumannii ABR2, ABR11, and ABS17, were used to evaluate antimicrobial susceptibility, biofilm inducibility, and gene transcription (abaI, adeB, adeG, adeJ, carO, and ompA). A significant increase in the MICs of different classes of antibiotics was observed in the biofilm cells. The formation of a biofilm was significantly induced in all the representative strains exposed to levofloxacin. The levels of gene transcription varied between bacterial genotypes, antibiotics, and antibiotic concentrations. The upregulation of adeG correlated with biofilm induction. The consistent upregulation of adeG and abaI was detected in A-III-type A. baumannii in response to levofloxacin and meropenem (1/8 to 1/2× the MIC), conditions which resulted in the greatest extent of biofilm induction. This study demonstrates a potential role of the AdeFGH efflux pump in the synthesis and transport of autoinducer molecules during biofilm formation, suggesting a link between low-dose antimicrobial therapy and a high risk of biofilm infections caused by A. baumannii. This study provides useful information for the development of antibiofilm strategies.
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In Vitro activities of combinations of rifampin with other antimicrobials against multidrug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2014; 59:1466-71. [PMID: 25534730 DOI: 10.1128/aac.04089-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antimicrobial treatment of multidrug-resistant (MDR) Acinetobacter baumannii infections has become a great challenge for medical staff all over the world. Increasing numbers of MDR A. baumannii infections have been identified and reported, but effective clinical treatments for them are decreasing. The objective of this study was to investigate the in vitro activities of combinations of rifampin (an established antimicrobial) and other antimicrobials, including biapenem, colistin, and tigecycline, against 73 clinical isolates of MDR A. baumannii. In total, 73 clinical isolates of MDR A. baumannii were collected from two A-level general hospitals in Beijing, and the MICs of rifampin, biapenem, colistin, and tigecycline were determined. The checkerboard method was used to determine the fractional inhibitory concentration indices (FICIs), that is, whether the combinations acted synergistically against these isolates. The MIC50, MIC90, and MICrange of rifampin combined with biapenem, colistin, and tigecycline against the isolates were clearly lower than those for four antimicrobials (rifampin, biapenem, colistin, and tigecycline) that were used alone. Combinations of rifampin with biapenem, colistin, and tigecycline individually demonstrated the following interactions: synergistic interactions (FICI ≤ 0.5) for 31.51%, 34.25%, and 31.51% of the isolates, partially synergistic interactions (0.5 < FICI < 1) for 49.31%, 43.83%, and 47.94% of the isolates, and additive interactions (FICI = 1) for 19.18%, 21.92%, and 20.55% of the isolates, respectively. There were no indifferent (1 < FICI < 4) or antagonistic (FICI ≥ 4) interactions. Therefore, combinations of rifampin with biapenem, colistin, or tigecycline may be future therapeutic alternatives for the treatment of MDR A. baumannii infections.
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Mart’yanov SV, Zhurina MV, El’-Registan GI, Plakunov VK. Activation of formation of bacterial biofilms by azithromycin and prevention of this effect. Microbiology (Reading) 2014. [DOI: 10.1134/s0026261714060113] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Gentile V, Frangipani E, Bonchi C, Minandri F, Runci F, Visca P. Iron and Acinetobacter baumannii Biofilm Formation. Pathogens 2014; 3:704-19. [PMID: 25438019 PMCID: PMC4243436 DOI: 10.3390/pathogens3030704] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/09/2014] [Accepted: 08/12/2014] [Indexed: 01/19/2023] Open
Abstract
Acinetobacter baumannii is an emerging nosocomial pathogen, responsible for infection outbreaks worldwide. The pathogenicity of this bacterium is mainly due to its multidrug-resistance and ability to form biofilm on abiotic surfaces, which facilitate long-term persistence in the hospital setting. Given the crucial role of iron in A. baumannii nutrition and pathogenicity, iron metabolism has been considered as a possible target for chelation-based antibacterial chemotherapy. In this study, we investigated the effect of iron restriction on A. baumannii growth and biofilm formation using different iron chelators and culture conditions. We report substantial inter-strain variability and growth medium-dependence for biofilm formation by A. baumannii isolates from veterinary and clinical sources. Neither planktonic nor biofilm growth of A. baumannii was affected by exogenous chelators. Biofilm formation was either stimulated by iron or not responsive to iron in the majority of isolates tested, indicating that iron starvation is not sensed as an overall biofilm-inducing stimulus by A. baumannii. The impressive iron withholding capacity of this bacterium should be taken into account for future development of chelation-based antimicrobial and anti-biofilm therapies.
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Affiliation(s)
- Valentina Gentile
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
| | - Emanuela Frangipani
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
| | - Carlo Bonchi
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
| | - Fabrizia Minandri
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
| | - Federica Runci
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
| | - Paolo Visca
- Department of Sciences, Roma Tre University, Viale Marconi 446, 00146 Rome, Italy.
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Kusada H, Hanada S, Kamagata Y, Kimura N. The effects of N-acylhomoserine lactones, β-lactam antibiotics and adenosine on biofilm formation in the multi-β-lactam antibiotic-resistant bacterium Acidovorax sp. strain MR-S7. J Biosci Bioeng 2014; 118:14-9. [DOI: 10.1016/j.jbiosc.2013.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 12/03/2013] [Accepted: 12/13/2013] [Indexed: 10/25/2022]
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Epidemic diffusion of OXA-23-producing Acinetobacter baumannii isolates in Italy: results of the first cross-sectional countrywide survey. J Clin Microbiol 2014; 52:3004-10. [PMID: 24920776 DOI: 10.1128/jcm.00291-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
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 MIC50 and MIC90 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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Fothergill JL, Winstanley C, James CE. Novel therapeutic strategies to counterPseudomonas aeruginosainfections. Expert Rev Anti Infect Ther 2014; 10:219-35. [DOI: 10.1586/eri.11.168] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Perez LRR. Acinetobacter baumannii displays inverse relationship between meropenem resistance and biofilm production. J Chemother 2014; 27:13-6. [PMID: 24621167 DOI: 10.1179/1973947813y.0000000159] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
In this study the ability for biofilm production among meropenem (MEM)-resistant and -susceptible Acinetobacter baumannii isolates was verified. MEM susceptibility and biofilm production were screened in 116 isolates. Meropenem-resistant A. baumannii isolates showed a reduced ability to produce biofilms compared to those susceptible to MEM (P<0.0001). The results suggest an inverse relationship between biofilm production and MEM resistance in nosocomial A. baumanni isolates.
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Kim HS, Park HD. Ginger extract inhibits biofilm formation by Pseudomonas aeruginosa PA14. PLoS One 2013; 8:e76106. [PMID: 24086697 PMCID: PMC3785436 DOI: 10.1371/journal.pone.0076106] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 08/21/2013] [Indexed: 01/11/2023] Open
Abstract
Bacterial biofilm formation can cause serious problems in clinical and industrial settings, which drives the development or screening of biofilm inhibitors. Some biofilm inhibitors have been screened from natural products or modified from natural compounds. Ginger has been used as a medicinal herb to treat infectious diseases for thousands of years, which leads to the hypothesis that it may contain chemicals inhibiting biofilm formation. To test this hypothesis, we evaluated ginger's ability to inhibit Pseudomonas aeruginosa PA14 biofilm formation. A static biofilm assay demonstrated that biofilm development was reduced by 39-56% when ginger extract was added to the culture. In addition, various phenotypes were altered after ginger addition of PA14. Ginger extract decreased production of extracellular polymeric substances. This finding was confirmed by chemical analysis and confocal laser scanning microscopy. Furthermore, ginger extract formed noticeably less rugose colonies on agar plates containing Congo red and facilitated swarming motility on soft agar plates. The inhibition of biofilm formation and the altered phenotypes appear to be linked to a reduced level of a second messenger, bis-(3'-5')-cyclic dimeric guanosine monophosphate. Importantly, ginger extract inhibited biofilm formation in both Gram-positive and Gram-negative bacteria. Also, surface biofilm cells formed with ginger extract detached more easily with surfactant than did those without ginger extract. Taken together, these findings provide a foundation for the possible discovery of a broad spectrum biofilm inhibitor.
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Affiliation(s)
- Han-Shin Kim
- School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, South Korea
| | - Hee-Deung Park
- School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul, South Korea
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Giannouli M, Antunes LCS, Marchetti V, Triassi M, Visca P, Zarrilli R. Virulence-related traits of epidemic Acinetobacter baumannii strains belonging to the international clonal lineages I-III and to the emerging genotypes ST25 and ST78. BMC Infect Dis 2013; 13:282. [PMID: 23786621 PMCID: PMC3691691 DOI: 10.1186/1471-2334-13-282] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 06/18/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii is responsible for large epidemics in hospitals, where it can persist for long time on abiotic surfaces. This study investigated some virulence-related traits of epidemic A. baumannii strains assigned to distinct MLST genotypes, including those corresponding to the international clones I-III as well as emerging genotypes responsible for recent epidemics. METHODS Genotyping of bacteria was performed by PFGE analysis and MLST according to the Pasteur's scheme. Biofilm formation on polystyrene plates was assessed by crystal violet staining; resistance to desiccation was evaluated on glass cover-slips when kept at room-temperature and 31% relative humidity; adherence to and invasion of A549 human alveolar epithelial cells were determined by the analysis of viable bacteria associated with or internalized by A549 human alveolar epithelial cells; Galleria mellonella killing assays were used to analyze the virulence of A. baumannii in vivo. RESULTS The ability to form biofilm was significantly higher for A. baumannnii strains assigned to ST2 (international clone II), ST25 and ST78 compared to other STs. All A. baumannii strains survived on dry surfaces for over 16 days, and strains assigned to ST1 (international clone I) and ST78 survived for up to 89 and 96 days, respectively. Adherence to A549 pneumocytes was higher for strains assigned to ST2, ST25 and ST78 than other genotypes; a positive correlation exists between adherence and biofilm formation. Strains assigned to ST78 also showed significantly higher ability to invade A549 cells. No significant differences in the killing of G. mellonella worms were found among strains. CONCLUSIONS Elevated resistance to desiccation, high biofilm-forming capacity on abiotic surfaces and adherence to A549 cells might have favoured the spread and persistence in the hospital environment of A. baumannii strains assigned to the international clones I and II and to the emerging genotypes ST25 and ST78.
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Affiliation(s)
- Maria Giannouli
- Department of Public Health, University of Naples Federico II, Naples, Italy
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Duarte AF, Ferreira S, Oliveira R, Domingues FC. Effect of Coriander Oil (Coriandrum sativum) on Planktonic and Biofilm Cells of Acinetobacter baumannii. Nat Prod Commun 2013. [DOI: 10.1177/1934578x1300800532] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The increasing incidence of hospital-acquired infections caused by multi-drug resistant pathogens, such as Acinetobacter baumannii, coupled with the low efficacy of drugs and rising treatment costs has created interest in the potential antimicrobial properties of natural products. The main objective of this work was to determine the effect of coriander essential oil on Acinetobacter baumannii in different growth phases, as well as its ability to inhibit the formation or eradication of biofilms. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of coriander oil using a microdilution broth susceptibility assay was determined. The effects of different concentrations of coriander oil (ranging from 0.125 to 4×MIC) on biofilm formation and on established biofilm were tested using 96-well microtiter plates. Crystal violet assay was used as indicator of total biofilm biomass and the biofilm viability was assessed with a XTT staining method. It was found that coriander oil presented significant antibacterial activity against all tested strains of A. baumannii, with MIC values between 1 and 4 μL/mL. The MBC values were the same as the MIC, being an indicator of the bactericidal activity of this essential oil. In what concerns the effect of this essential oil on biofilm formation inhibition was observed of at least 85% of biomass formation by all A. baumannii strains using 2×MIC of coriander oil, in addition to a decrease in the metabolic activity of the cells. After exposure to coriander oil, a decrease in 24 h and 48 h-old biofilm biomass and metabolism was seen for all tested concentrations, even with sub-inhibitory concentrations. Coriander essential oil proved to have a significant antibacterial and anti-biofilm activity and should be considered in the development of future disinfectants to control A. baumannii dissemination.
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Affiliation(s)
- Andreia F. Duarte
- CICS-UBI-Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Susana Ferreira
- CICS-UBI-Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Rosário Oliveira
- Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Fernanda C. Domingues
- CICS-UBI-Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
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48
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Djeribi R, Boucherit Z, Bouchloukh W, Zouaoui W, Latrache H, Hamadi F, Menaa B. A study of pH effects on the bacterial surface physicochemical properties of Acinetobacter baumannii. Colloids Surf B Biointerfaces 2013; 102:540-5. [DOI: 10.1016/j.colsurfb.2012.08.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 08/16/2012] [Accepted: 08/28/2012] [Indexed: 10/27/2022]
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49
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Migliavacca R, Espinal P, Principe L, Drago M, Fugazza G, Roca I, Nucleo E, Bracco S, Vila J, Pagani L, Luzzaro F. Characterization of resistance mechanisms and genetic relatedness of carbapenem-resistant Acinetobacter baumannii isolated from blood, Italy. Diagn Microbiol Infect Dis 2012; 75:180-6. [PMID: 23265293 DOI: 10.1016/j.diagmicrobio.2012.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/11/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
Abstract
The aim of this study was to characterize the resistance mechanisms and genetic relatedness of 21 carbapenem-resistant Acinetobacter baumannii blood isolates collected in Italy during a 1-year multicenter prospective surveillance study. Genes coding for carbapenemase production were identified by polymerase chain reaction (PCR) and sequencing. Pulsed-field gel electrophoresis (PFGE), multiplex PCRs for group identification, and multilocus sequence typing (MLST) were used to determine genetic relationships. Carbapenem resistance was consistently related to the production of oxacillinases, mostly the plasmid-mediated OXA-58 enzyme. Strains producing the OXA-23 enzyme (chromosomally mediated) were also detected. Seven PFGE clones were identified, some of which being related to international (ICL- I and ICL-II) or national clonal lineages. Multiplex PCRs identified 4 different groups (group 2 being dominant), further distinguishable in 6 sequence types by MLST. The heterogeneity of profiles highlights the diffusion of international and national clonal lineages in Italy. Continuous surveillance is needed for monitoring the spread of these worrisome strains equipped with multiple drug resistance mechanisms.
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Affiliation(s)
- Roberta Migliavacca
- Department of Clinical Surgical Diagnostic and Pediatric Sciences, Section of Microbiology, University of Pavia, Pavia, Italy
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50
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Dhabaan GN, AbuBakar S, Shorman MA, Hassan H. In vitro activity of tigecycline against Acinetobacter baumannii isolates from a teaching hospital in Malaysia. J Chemother 2012; 24:87-92. [PMID: 22546763 DOI: 10.1179/1120009x12z.00000000017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The In vitro susceptibility of clinical and environmental isolates of Acinetobacter baumannii to tigecycline and other antibiotics was determined by disk diffusion method. The E-test was used to determine the minimum inhibitory concentration (MIC). The growth curves of tigecycline treated environmental and clinical strains were established. Fifty-seven percent and 75% of the clinical and environmental isolates were MDR strains, respectively. Ninety-five percent of the clinical isolates were susceptible to tigecycline and 5% showed intermediate resistance with MIC ranging between 0.032 and 3 mg/l. Tigecycline susceptible and intermediate resistance among the environmental isolates were 40% and 60%, respectively, with a significantly lower MIC range of 0.5-4 mg/l. The bacterial growth curves demonstrated the higher ability of the environmental strains to tolerate the antibiotic effects than the clinical strains. The relatively high resistance profile among the environmental isolate suggests an insidious emergence of tigecycline resistance amongst A. baumannii. Strict infection control procedures are imperative to prevent the dissemination of tigecycline-resistant A. baumannii strains in the hospital environment.
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Affiliation(s)
- Ghulam N Dhabaan
- Tropical Infectious Diseases Research and Education Center, Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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