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Jeon CH, Kim SH, Kim HT, Park KJ, Wi YM. Ineffectiveness of colistin monotherapy in treating carbapenem-resistant Acinetobacter baumannii Pneumonia: A retrospective single-center cohort study. J Infect Public Health 2024; 17:774-779. [PMID: 38518683 DOI: 10.1016/j.jiph.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/21/2024] [Accepted: 03/04/2024] [Indexed: 03/24/2024] Open
Abstract
BACKGROUND Acinetobacter baumannii, a common carbapenem-resistant gram-negative bacillus, usually causes nosocomial infections. Colistin has been used for carbapenem-resistant A. baumannii (CRAB) infections; however, only a few studies have evaluated colistin as a treatment option compared to appropriate controls. We investigated the effectiveness of colistin monotherapy in treating CRAB pneumonia compared to those treated without an active drug. METHODS Adult patients (≥ 18 years) with CRAB isolated from respiratory specimens were screened from September 2017 to August 2022. Only patients with pneumonia treated with colistin monotherapy (colistin group) were included and compared to those without any active antibiotics (no active antibiotics [NAA] group). The primary and secondary outcomes were 30-day all-cause mortality and acute kidney injury within 30 days. The inverse probability of the treatment-weighted Cox proportional hazard model was used to compare mortality between groups. RESULTS Among the 826 adult patients with CRAB in their respiratory specimens, 45 and 123 patients were included in the colistin and NAA groups, respectively. Most of the CRAB pneumonia (91.1%) cases were hospital-acquired pneumonia. The 30-day all-cause mortality rates in the colistin and NAA groups were 58.3% and 56.1%, respectively, and no difference was observed after adjustments (adjusted hazard ratio, 0.74; 95% CI, 0.47-1.17). The incidence of acute kidney injury was higher in the colistin group (65.3%) compared to the NAA group (39.0%) (P = 0.143). CONCLUSIONS Colistin monotherapy did not significantly improve treatment outcomes for CRAB pneumonia. The development and evaluation of new antimicrobials for CRAB pneumonia should be advocated in clinical practice.
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Affiliation(s)
- Cheon-Hoo Jeon
- Department of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Republic of Korea
| | - Si-Ho Kim
- Department of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Republic of Korea.
| | - Hyoung-Tae Kim
- Department of Laboratory Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - Kyoung-Jin Park
- Department of Laboratory Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Republic of Korea
| | - Yu Mi Wi
- Department of Infectious Diseases, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Republic of Korea
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2
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Jo J, Lee JY, Cho H, Ko KS. Treatment of Colistin Dependence-Developing Acinetobacter baumannii with Antibiotic Combinations at Subinhibitory Concentrations. Microb Drug Resist 2023; 29:448-455. [PMID: 37379479 DOI: 10.1089/mdr.2022.0205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023] Open
Abstract
Recent studies have revealed that colistin dependence frequently develops in colistin-susceptible Acinetobacter baumannii isolates. Despite resistance in parental strains, colistin-dependent mutants showed increased susceptibility to several antibiotics, which suggests the possibility of developing strategies to eliminate multidrug-resistant (MDR) A. baumannii. We investigated in vitro and in vivo efficacy of combinations of colistin and other antibiotics using MDR A. baumannii strains H08-391, H06-855, and H09-94, which are colistin-susceptible but develops colistin dependence upon exposure to colistin. An in vitro time-killing assay, a checkerboard assay, and an antibiotic treatment assay using Galleria mellonella larvae were performed. Although a single treatment of colistin at a high concentration did not prevent colistin dependence, combinations of colistin with other antibiotics at subinhibitory concentrations, especially amikacin, eradicated the strains by inhibiting the development of colistin dependence, in the in vitro time-killing assay. Only 40% of G. mellonella larvae infected by A. baumannii survived with colistin treatment alone; however, all or most of them survived following treatment with the combination of colistin and other antibiotics (amikacin, ceftriaxone, and tetracycline). Our results suggest the possibility of the combination of colistin and amikacin or other antibiotics as one of therapeutic options against A. baumannii infections by eliminating colistin-dependent mutants.
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Affiliation(s)
- Jeongwoo Jo
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Ji Young Lee
- Research Institute for Future Medical Science, Chungnam National University Sejong Hospital, Sejong, Republic of Korea
| | - Hongbaek Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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3
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Paredes-Amaya CC, Ulloa MT, García-Angulo VA. Fierce poison to others: the phenomenon of bacterial dependence on antibiotics. J Biomed Sci 2023; 30:67. [PMID: 37574554 PMCID: PMC10424368 DOI: 10.1186/s12929-023-00963-x] [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: 04/25/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.
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Affiliation(s)
- Claudia C Paredes-Amaya
- Microbiology Department, Escuela de Ciencias Básicas, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | - María Teresa Ulloa
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile
- Vertebral I+D+i - Corporation for Assistance for Burned Children (Coaniquem), Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile.
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4
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Zafer MM, Hussein AFA, Al-Agamy MH, Radwan HH, Hamed SM. Retained colistin susceptibility in clinical Acinetobacter baumannii isolates with multiple mutations in pmrCAB and lpxACD operons. Front Cell Infect Microbiol 2023; 13:1229473. [PMID: 37600939 PMCID: PMC10436201 DOI: 10.3389/fcimb.2023.1229473] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023] Open
Abstract
The progressive increase in the resistance rates to first- and second-line antibiotics has forced the reuse of colistin as last-line treatment for Acinetobacter baumannii infections, but the emergence of colistin-resistant strains is not uncommon. This has been long linked to acquired chromosomal mutations in the operons pmrCAB and lpxACD. Hence, such mutations are routinely screened in colistin-resistant strains by most studies. The current study was designed to explore the possible existence of pmrCAB and lpxACD mutations in colistin-susceptible isolates. For this purpose, the whole genome sequences of eighteen multi-/extensively drug resistant A. baumannii were generated by Illumina sequencing and screened for missense mutations of the operons pmrCAB and lpxACD. Most of the isolates belonged to global clones (GCs) including GC1 (n=2), GC2 (n=7), GC7 (n=2), GC9 (n=3), and GC11 (n=1). The minimum inhibitory concentrations (MICs) of colistin were determined by the broth microdilution assay. Seventeen isolates were fully susceptible to colistin with MICs ranging from (≤0.125 to 0.5 µg/ml). Interestingly, all colistin-susceptible isolates carried missense mutations in pmrCAB and lpxACD operons with reference to A. baumannii ATCC 19606. Overall, 34 mutations were found. Most substitutions were detected in pmrC (n=20) while no mutations were found in pmrA or lpxA. Notably, the mutation pattern of the two operons was almost conserved among the isolates that belonged to the same sequence type (ST) or GC. This was also confirmed by expanding the analysis to include A. baumannii genomes deposited in public databases. Here, we demonstrated the possible existence of missense mutations in pmrCAB and lpxACD operons in colistin-susceptible isolates, shedding light on the importance of interpreting mutations with reference to colistin-susceptible isolates of the same ST/GC to avoid the misleading impact of the ST/GC-related polymorphism. In turn, this may lead to misinterpretation of mutations and, hence, overlooking the real players in colistin resistance that are yet to be identified.
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Affiliation(s)
- Mai M. Zafer
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University, Cairo, Egypt
| | - Amira F. A. Hussein
- Clinical and Chemical Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
- Faculty of Applied Health Science, Galala University, Cairo, Egypt
| | - Mohamed H. Al-Agamy
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Hesham H. Radwan
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Samira M. Hamed
- Department of Microbiology and Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), 6th of October, Giza, Egypt
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Dablool AS. An Antibiogram Study for Urine Culture Testing in Makkah Region Hospitals. Cureus 2023; 15:e36012. [PMID: 37041904 PMCID: PMC10084737 DOI: 10.7759/cureus.36012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2023] [Indexed: 03/13/2023] Open
Abstract
BACKGROUND The antibiogram profile could be helpful in the selection of the most appropriate antimicrobial treatment for microbial infection and even useful to monitor antibiotic resistance. OBJECTIVE This study aims to identify the bacteria in the urine through urine culture and perform their antibiogram to determine the resistance profile between antibiotics and urine tract infection (UTI)-causing bacteria and to determine the effective and non-effective antibiotics. METHODS The study was based on urine culture data from five Makkah hospitals in the Kingdom of Saudi Arabia (KSA). RESULTS A total of 1000 pathogens were found in the urine culture; 899 were bacterial isolates, and 101 were Candida spp. Seven hundred and seventy-seven of the 899 bacteria isolates were gram-positive, while 122 were gram-negative bacteria. Escherichia coli (44%) was the most frequent UTI-causing bacteria, followed by Klebsiella spp. (20%), Pseudomonas aeruginosa (6%), S. aureus (5.5%), Enterococcus faecalis (4.5%), Enterobacter spp. (2%), and Proteus spp. (1%). There was clear evidence that ampicillin, cefepime, erythromycin, and moxifloxacin were not effective antibiotics for uropathogens in the Makkah area, KSA. The multiple drug resistance (MDR), extensively drug-resistant (XDR), extended spectrum beta lactamase (ESBL), CR, and quinolones resistance (QR) were higher in the gram-negative bacilli. The pandrug resistance (PDR) and AmpC seemed to have fewer ratios of UTIs caused by gram-negative bacteria. On the other hand, S. aureus of the gram-positive type was also involved in the UTI and had a higher ratio of MDR, QR, and methicillin-resistant Staphylococcus aureus (MRSA).
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Kamoshida G, Yamada N, Nakamura T, Yamaguchi D, Kai D, Yamashita M, Hayashi C, Kanda N, Sakaguchi M, Morimoto H, Sawada T, Okada T, Kaya Y, Takemoto N, Yahiro K. Preferential Selection of Low-Frequency, Lipopolysaccharide-Modified, Colistin-Resistant Mutants with a Combination of Antimicrobials in Acinetobacter baumannii. Microbiol Spectr 2022; 10:e0192822. [PMID: 36173297 PMCID: PMC9602988 DOI: 10.1128/spectrum.01928-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 12/31/2022] Open
Abstract
Colistin, which targets lipopolysaccharide (LPS), is used as a last-resort drug against severe infections caused by drug-resistant Acinetobacter baumannii. However, A. baumannii possesses two colistin-resistance mechanisms. LPS modification caused by mutations in pmrAB genes is often observed in clinical isolates of multidrug-resistant Gram-negative pathogens. In addition to LPS modification, A. baumannii has a unique colistin resistance mechanism, a complete loss of LPS due to mutations in the lpxACD genes, which are involved in LPS biosynthesis. This study aimed to elucidate the detailed mechanism of the emergence of colistin-resistant A. baumannii using strains with the same genetic background. Various colistin-resistant strains were generated experimentally using colistin alone and in combination with other antimicrobials, such as meropenem and ciprofloxacin, and the mutation spectrum was analyzed. In vitro selection of A. baumannii in the presence of colistin led to the emergence of strains harboring mutations in lpxACD genes, resulting in LPS-deficient colistin-resistant strains. However, combination of colistin with other antimicrobials led to the selection of pmrAB mutant strains, resulting in strains with modified LPS (LPS-modified strains). Further, the LPS-deficient strains showed decreased fitness and increased susceptibility to many antibiotics and disinfectants. As LPS-deficient strains have a higher biological cost than LPS-modified strains, our findings suggested that pmrAB mutants are more likely to be isolated in clinical settings. We provide novel insights into the mechanisms of resistance to colistin and provide substantial solutions along with precautions for facilitating current research and treatment of colistin-resistant A. baumannii infections. IMPORTANCE Acinetobacter baumannii has developed resistance to various antimicrobial drugs, and its drug-resistant strains cause nosocomial infections. Controlling these infections has become a global clinical challenge. Carbapenem antibiotics are the frontline treatment drugs for infectious diseases caused by A. baumannii. For patients with infections caused by carbapenem-resistant A. baumannii, colistin-based therapy is often the only treatment option. However, A. baumannii readily acquires resistance to colistin. Many patients infected with colistin-resistant A. baumannii undergo colistin treatment before isolation of the colistin-resistant strain, and it is hypothesized that colistin resistance predominantly emerges under selective pressure during colistin therapy. Although the concomitant use of colistin and carbapenems has been reported to have a synergistic effect in vitro against carbapenem-resistant A. baumannii strains, our observations strongly suggest the need for attention to the emergence of strains with a modified lipopolysaccharide during treatment.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Noriteru Yamada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tomoka Nakamura
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daiki Yamaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daichi Kai
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Maho Yamashita
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Chiaki Hayashi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Nana Kanda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Moe Sakaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Hitoshi Morimoto
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Teppei Sawada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tomoko Okada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yuki Kaya
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
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7
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Kon H, Hameir A, Temkin E, Keren-Paz A, Schwartz D, Schechner V, Carmeli Y. Colistin Dependency among Colistin-Heteroresistant Acinetobacter baumannii Isolates. Microorganisms 2021; 10:58. [PMID: 35056508 PMCID: PMC8780235 DOI: 10.3390/microorganisms10010058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/23/2021] [Accepted: 12/26/2021] [Indexed: 11/16/2022] Open
Abstract
Colistin dependent (CD) isolates are dependent on colistin for optimal growth. Here we aimed to systematically determine the emergence of CD among colistin-heteroresistant carbapenem-resistant Acinetobacter baumannii (CRAB) isolates. We also examined the phenotypic characteristics of CD and the evolution of CD strains to overt resistance. Additionally, we examined whether detection of growth in blood cultures was impaired by CD. Heteroresistant isolates, as determined by population analysis profiling, were exposed to colistin; when the colony count with colistin was significantly higher than without, isolates were suspected to be CD. CD was confirmed by Etest and growth curves. CD strains with colistin minimum inhibitory concentrations > 2 mg/L after growth in colistin-free media were considered colistin-resistant. Of the 65 heteroresistant strains tested, eight became CD after colistin exposure. These strains attained higher colony counts and growth rates with colistin vs. without, and grew adjacent to the colistin Etest strip. CD strains exhibited increased susceptibilities to multiple antibiotics compared to their parent heteroresistant strains. All CD strains tested became colistin-resistant following growth without colistin. CD strains were detected in blood culture bottles, but time to detection was significantly prolonged compared with parent strains, suggesting that CD may lead to delay in detection of CRAB bacteremia.
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Affiliation(s)
- Hadas Kon
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
| | - Amichay Hameir
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
| | - Elizabeth Temkin
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
| | - Alona Keren-Paz
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
| | - David Schwartz
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
| | - Vered Schechner
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Yehuda Carmeli
- National Institute for Antibiotic Resistance and Infection Control, Ministry of Health, Tel Aviv 6423906, Israel; (H.K.); (A.H.); (E.T.); (A.K.-P.); (D.S.); (V.S.)
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
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Torres DA, Seth-Smith HMB, Joosse N, Lang C, Dubuis O, Nüesch-Inderbinen M, Hinic V, Egli A. Colistin resistance in Gram-negative bacteria analysed by five phenotypic assays and inference of the underlying genomic mechanisms. BMC Microbiol 2021; 21:321. [PMID: 34798825 PMCID: PMC8605564 DOI: 10.1186/s12866-021-02388-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/09/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Colistin is used against multi-drug resistant pathogens, yet resistance emerges through dissemination of plasmid-mediated genes (mcr) or chromosomal mutation of genes involved in lipopolysaccharide synthesis (i.e. mgrB, phoPQ, pmrCAB). Phenotypic susceptibility testing is challenging due to poor diffusion of colistin in agar media, leading to an underestimation of resistance. Performance of five phenotypic approaches was compared in the context of different molecular mechanisms of resistance. We evaluated Vitek 2® (bioMérieux, AST N242), Colistin MIC Test Strip (Liofilchem Diagnostici), UMIC (Biocentric), and Rapid Polymyxin™ NP test (ELITechGroup) against the standard broth microdilution (BMD) method. We used whole genome sequencing (WGS) to infer molecular resistance mechanisms. We analysed 97 Enterobacterales and non-fermenting bacterial isolates, largely clinical isolates collected up to 2018. Data was analysed by comparing susceptibility categories (susceptible or resistant) and minimal inhibitory concentrations (MIC). Susceptibility category concordance is the percentage of test results sharing the same category to BMD. MIC concordance was calculated similarly but considering ±1 MIC titre error range. We determined genomic diversity by core genome multi locus sequencing typing (cgMLST) and identified putative antimicrobial resistance genes using NCBI and CARD databases, and manual annotation. RESULTS Of 97 isolates, 54 (56%) were resistant with standard BMD. Highest susceptibility category concordance was achieved by Rapid Polymyxin™ NP (98.8%) followed by UMIC (97.9%), Colistin E-test MIC strip (96.9%) and Vitek 2® (95.6%). Highest MIC concordance was achieved by UMIC (80.4%), followed by Vitek 2® (72.5%) and Colistin E-test MIC strip (62.9%). Among resistant isolates, 23/54 (43%) were intrinsically resistant to colistin, whereas 31/54 (57%) isolates had acquired colistin resistance. Of these, mcr-1 was detected in four isolates and mcr-2 in one isolate. Non-synonymous mutations in mgrB, phoQ, pmrA, pmrB, and pmrC genes were encountered in Klebsiella pneumoniae, Escherichia coli, and Acinetobacter bereziniae resistant isolates. Mutations found in mgrB and pmrB were only identified in isolates exhibiting MICs of ≥16 mg/L. CONCLUSIONS The Rapid Polymyxin™ NP test showed highest categorical concordance and the UMIC test provided MIC values with high concordance to BMD. We found colistin resistance in diverse species occurred predominantly through spontaneous chromosomal mutation rather than plasmid-mediated resistance.
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Affiliation(s)
- Diana Albertos Torres
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Helena M B Seth-Smith
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Nicole Joosse
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Unilabs Bern-Mittelland, Bern, Switzerland
| | - Claudia Lang
- Clinical Microbiology, Viollier AG, Allschwil, Switzerland
| | - Olivier Dubuis
- Clinical Microbiology, Viollier AG, Allschwil, Switzerland
| | | | - Vladimira Hinic
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
| | - Adrian Egli
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland.
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland.
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9
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Abstract
In this study, we investigated the colistin heteroresistance patterns in Acinetobacter baumannii isolates. To identify colistin heteroresistance, population analysis profiling was performed for six in vitro colistin-susceptible A. baumannii isolates. Survival rates with and without prior exposure to colistin (at concentrations between 0 and 32 mg/L) were measured in media with and without colistin. Amino acid substitutions were also detected in colonies that survived in media with 4 mg/L colistin without further antibiotic treatment in six A. baumannii isolates. A stability test was also performed to investigate whether colistin resistance is maintained without antibiotic treatment. Although only three isolates showed typical colistin heteroresistance pattern, colistin-resistant populations were identified even without prior exposure to colistin in all A. baumannii isolates. Nearly all colonies of typical colistin-heteroresistant isolates (Type I heteroresistance) that survived after exposure to high colistin concentrations were found to be colistin-resistant, whereas no resistant colonies were identified in the other isolates (Type II heteroresistance). Stability tests showed that most of the surviving populations in media with 4 mg/L colistin without further antibiotic exposure failed to preserve resistance to colistin. Colistin-resistant populations also showed either no change in amino acid sequences, or diverse amino acid substitutions. We identified two types of colistin heteroresistance in A. baumannii isolates. Because Type I colistin-heteroresistant A. baumannii isolates could not be eradicated in vitro by high concentrations of colistin, differentiating two colistin heteroresistance types would be important for the treatment of A. baumannii infections using colistin.
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Affiliation(s)
- Yoon-Kyoung Hong
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Hyunkeun Kim
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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10
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Onime LA, Oyama LB, Thomas BJ, Gani J, Alexander P, Waddams KE, Cookson A, Fernandez-Fuentes N, Creevey CJ, Huws SA. The rumen eukaryotome is a source of novel antimicrobial peptides with therapeutic potential. BMC Microbiol 2021; 21:105. [PMID: 33832427 PMCID: PMC8034185 DOI: 10.1186/s12866-021-02172-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/25/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The rise of microbial antibiotic resistance is a leading threat to the health of the human population. As such, finding new approaches to tackle these microbes, including development of novel antibiotics is vital. RESULTS In this study, we mined a rumen eukaryotic metatranscriptomic library for novel Antimicrobial peptides (AMPs) using computational approaches and thereafter characterised the therapeutic potential of the AMPs. We identified a total of 208 potentially novel AMPs from the ruminal eukaryotome, and characterised one of those, namely Lubelisin. Lubelisin (GIVAWFWRLAR) is an α-helical peptide, 11 amino acid long with theoretical molecular weight of 1373.76 D. In the presence of Lubelisin, strains of methicillin-resistant Staphylococcus aureus (MRSA) USA300 and EMRSA-15 were killed within 30 min of exposure with ≥103 and 104 CFU/mL reduction in viable cells respectively. Cytotoxicity of Lubelisin against both human and sheep erythrocytes was low resulting in a therapeutic index of 0.43. Membrane permeabilisation assays using propidium iodide alongside transmission electron microscopy revealed that cytoplasmic membrane damage may contribute to the antimicrobial activities of Lubelisin. CONCLUSIONS We demonstrate that the rumen eukaryotome is a viable source for the discovery of antimicrobial molecules for the treatment of bacterial infections and further development of these may provide part of the potential solution to the ongoing problem of antimicrobial resistance. The role of these AMPs in the ecological warfare within the rumen is also currently unknown.
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Affiliation(s)
- Lucy A Onime
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK
| | - Linda B Oyama
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | - Benjamin J Thomas
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | - Jurnorain Gani
- Institute of Infection and Immunity, St. George's University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Peter Alexander
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | - Kate E Waddams
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK
| | - Alan Cookson
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK
| | - Narcis Fernandez-Fuentes
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK
| | - Christopher J Creevey
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | - Sharon A Huws
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK.
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11
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Colistin Dependence in Extensively Drug-Resistant Acinetobacter baumannii Strain Is Associated with IS Ajo2 and IS Aba13 Insertions and Multiple Cellular Responses. Int J Mol Sci 2021; 22:ijms22020576. [PMID: 33430070 PMCID: PMC7827689 DOI: 10.3390/ijms22020576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 02/06/2023] Open
Abstract
The nosocomial opportunistic Gram-negative bacterial pathogen Acinetobacter baumannii is resistant to multiple antimicrobial agents and an emerging global health problem. The polymyxin antibiotic colistin, targeting the negatively charged lipid A component of the lipopolysaccharide on the bacterial cell surface, is often considered as the last-resort treatment, but resistance to colistin is unfortunately increasing worldwide. Notably, colistin-susceptible A. baumannii can also develop a colistin dependence after exposure to this drug in vitro. Colistin dependence might represent a stepping stone to resistance also in vivo. However, the mechanisms are far from clear. To address this issue, we combined proteogenomics, high-resolution microscopy, and lipid profiling to characterize and compare A. baumannii colistin-susceptible clinical isolate (Ab-S) of to its colistin-dependent subpopulation (Ab-D) obtained after subsequent passages in moderate colistin concentrations. Incidentally, in the colistin-dependent subpopulation the lpxA gene was disrupted by insertion of ISAjo2, the lipid A biosynthesis terminated, and Ab-D cells displayed a lipooligosaccharide (LOS)-deficient phenotype. Moreover, both mlaD and pldA genes were perturbed by insertions of ISAjo2 and ISAba13, and LOS-deficient bacteria displayed a capsule with decreased thickness as well as other surface imperfections. The major changes in relative protein abundance levels were detected in type 6 secretion system (T6SS) components, the resistance-nodulation-division (RND)-type efflux pumps, and in proteins involved in maintenance of outer membrane asymmetry. These findings suggest that colistin dependence in A. baumannii involves an ensemble of mechanisms seen in resistance development and accompanied by complex cellular events related to insertional sequences (ISs)-triggered LOS-deficiency. To our knowledge, this is the first study demonstrating the involvement of ISAjo2 and ISAba13 IS elements in the modulation of the lipid A biosynthesis and associated development of dependence on colistin.
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12
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Lunha K, Thet KT, Ngudsuntia A, Charoensri N, Lulitanond A, Tavichakorntrakool R, Wonglakorn L, Faksri K, Chanawong A. PmrB mutations including a novel 10-amino acid repeat sequence insertion associated with low-level colistin resistance in carbapenem-resistant Acinetobacter baumannii. INFECTION GENETICS AND EVOLUTION 2020; 85:104577. [PMID: 33007498 DOI: 10.1016/j.meegid.2020.104577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 09/22/2020] [Accepted: 09/27/2020] [Indexed: 10/23/2022]
Abstract
The global emergence of colistin resistance in carbapenem-resistant Acinetobacter baumannii (CRAB) clinical isolates is a serious public health concern. We therefore aimed to investigate colistin resistance mechanisms in 5 colistin-resistant (COL-R) CRAB isolates collected from Thai patients in 2016 by whole genome sequencing (WGS) compared with those of 5 colistin-intermediate (COL-I) CRAB isolates from the same period. All isolates were subjected to antimicrobial susceptibility testing, efflux pump inhibitor-based test and WGS. Mutations in known genes associated with colistin resistance were analyzed and deleterious mutations were then predicted by PROVEAN tool. The 10 CRAB isolates carried blaOXA-23 with the addition of blaOXA-58 in 1 isolate. All COL-R isolates exhibited colistin MICs of 4 μg/mL except for 1 isolate with that of 16 μg/mL. They belonged to ST2, ST16, ST23, ST164 and ST215, whereas the COL-I isolates with colistin MICs of ≤0.25-1 μg/mL were ST2, ST164 and ST215. Neither increased efflux pump activity nor mcr gene was found in any COL-R isolate. Three COL-R isolates contained different PmrB variants: a novel 10-amino acid (aa) repeat sequence insertion, VILGCILIFS between positions 27 and 28 (S27_A28insVILGCILIFS) in transmembrane domain (TM); a 1-aa insertion, alanine between positions 162 and 163 (A162_I163insA) in TM; and a 1-aa substitution, A226T in histidine kinase domain. One COL-R isolate possessed PmrA variant with A80V substitution. These alterations were predicted as deleterious. Mechanisms of colistin resistance in the remaining COL-R isolate were still unknown. In conclusion, the alterations in both PmrB and PmrA were predicted and suggested as initial mutations responsible for low-level colistin resistance in our CRAB isolates. Under selective pressure, these isolates may exhibit higher level colistin resistance by the additional mutations, leading to more therapeutic difficulties.
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Affiliation(s)
- Kamonwan Lunha
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Khin Thet Thet
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Arisa Ngudsuntia
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Aroonlug Lulitanond
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Ratree Tavichakorntrakool
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Lumyai Wonglakorn
- Clinical Microbiology Laboratory, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Kiatichai Faksri
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Aroonwadee Chanawong
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
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13
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Thet KT, Lunha K, Srisrattakarn A, Lulitanond A, Tavichakorntrakool R, Kuwatjanakul W, Charoensri N, Chanawong A. Colistin heteroresistance in carbapenem-resistant Acinetobacter baumannii clinical isolates from a Thai university hospital. World J Microbiol Biotechnol 2020; 36:102. [PMID: 32613355 PMCID: PMC7327205 DOI: 10.1007/s11274-020-02873-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/21/2020] [Indexed: 01/22/2023]
Abstract
Colistin is the last resort for the treatment of infections with carbapenem-resistant (CR) Gram-negative bacteria particularly Acinetobacter baumannii (CRAB). Currently, both colistin-resistant and -heteroresistant A. baumannii isolates have been reported globally. We therefore investigated the colistin heteroresistance rate in 75 non-duplicate colistin-susceptible CRAB clinical isolates from a Thai university collected in 2016. Minimum inhibitory concentrations (MICs) of colistin for all isolates were determined by broth microdilution method and carbapenemase genes were detected by PCR methods. All isolates were genotyped by ERIC-PCR method and screened for colistin heteroresistance by modified population analysis profile (PAP) method. The colistin MIC range for the 75 isolates was 0.5-2 µg/mL, with MIC50 and MIC90 of 1 and 2 µg/mL, respectively. Thirty-three isolates (44%) were considered colistin-heteroresistant with subpopulations growing at 3-8 μg/mL of colistin. After three daily passages of the subpopulations on antibiotic-free medium, their colistin MICs ranged from 4 to > 32 µg/mL, with MIC50 and MIC90 of 32 and > 32 µg/mL, respectively. Eight different ERIC-PCR profiles were obtained among the 33 isolates and all carried blaOXA-23-like. The high rate of colistin heteroresistance in the CRAB isolates highlights the possibility of treatment failure of CRAB infections by colistin due to the selection of colistin-resistant subpopulations.
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Affiliation(s)
- Khin Thet Thet
- Medical Technology Programme, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Kamonwan Lunha
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Arpasiri Srisrattakarn
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Aroonlug Lulitanond
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Ratree Tavichakorntrakool
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Waewta Kuwatjanakul
- Clinical Microbiology Unit, Faculty of Medicine, Srinagarind Hospital, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Aroonwadee Chanawong
- Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand.
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14
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Lima WG, Brito JCM, Cardoso BG, Cardoso VN, de Paiva MC, de Lima ME, Fernandes SOA. Rate of polymyxin resistance among Acinetobacter baumannii recovered from hospitalized patients: a systematic review and meta-analysis. Eur J Clin Microbiol Infect Dis 2020; 39:1427-1438. [PMID: 32533271 DOI: 10.1007/s10096-020-03876-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 03/23/2020] [Indexed: 01/08/2023]
Abstract
We conducted a systematic review and meta-analysis to determine the rate of polymyxin resistance among Acinetobacter baumannii isolates causing infection in hospitalized patients around the world during the period of 2010-2019. The systematic review was performed on September 1, 2019, using PubMed/MEDLINE, Scopus, and Web of Science; studies published after January 1, 2010, were selected. The data were summarized in tables, critically analyzed, and treated statistically using the RStudio® Software with Meta package and Metaprop Command. After applying exclusion factors, 41 relevant studies were selected from 969 articles identified on literature search. The overall rate of polymyxin-resistant A. baumannii (PRAB) related to hospitalized patients was estimated to be 13% (95% CI, 0.06-0.27), where a higher rate was observed in America (29%; 95% CI, 0.12-0.55), followed by Europe (13%; 95% CI, 0.02-0.52), and Asia (10%; 95% CI, 0.02-0.32). The extensive use of polymyxins on veterinary to control bacterial infection and growth promotion, as well as the resurgence in prescription and use of polymyxins in the clinics against carbapenem-resistant gram-negative bacteria, may have contributed to the increased incidence of PRAB. The findings of this meta-analysis revealed that the rate of PRAB recovered from hospitalized patients is distinctively high. Thus, action needs to be taken to develop strategies to combat the clinical incidence of PRAB-induced hospital infections.
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Affiliation(s)
- William Gustavo Lima
- Laboratório de Radioisótopos, Departamento de Análises Clinicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. .,Laboratório de Diagnóstico Laboratorial e Microbiologia Clínica, Campus Centro-Oeste/Dona Lindu, Universidade Federal de São João del-Rei, Rua Sebastião Gonçalves Coelho, 400, Divinópolis, MG, 35501-293, Brazil.
| | - Júlio César Moreira Brito
- Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil.,Programa de Pós-Graduação em Inovação Tecnológica e Biofarmacêutica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bárbara Gatti Cardoso
- Laboratório de Radioisótopos, Departamento de Análises Clinicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Valbert Nascimento Cardoso
- Laboratório de Radioisótopos, Departamento de Análises Clinicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Magna Cristina de Paiva
- Laboratório de Diagnóstico Laboratorial e Microbiologia Clínica, Campus Centro-Oeste/Dona Lindu, Universidade Federal de São João del-Rei, Rua Sebastião Gonçalves Coelho, 400, Divinópolis, MG, 35501-293, Brazil
| | - Maria Elena de Lima
- Programa de Pós-Graduação em Inovação Tecnológica e Biofarmacêutica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.,Instituto de Ensino e Pesquisa, Santa Casa-Belo Horizonte, Belo Horizonte, Brazil
| | - Simone Odília Antunes Fernandes
- Laboratório de Radioisótopos, Departamento de Análises Clinicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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15
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Marano V, Marascio N, Pavia G, Lamberti AG, Quirino A, Musarella R, Casalinuovo F, Mazzitelli M, Trecarichi EM, Torti C, Matera G, Liberto MC. Identification of pmrB mutations as putative mechanism for colistin resistance in A. baumannii strains isolated after in vivo colistin exposure. Microb Pathog 2020; 142:104058. [PMID: 32058026 DOI: 10.1016/j.micpath.2020.104058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/20/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
Colistin resistance among extensively-resistant Acinetobacter baumannii isolates is a serious health-care problem. Alterations in PmrA-PmrB two-component system have been associated with resistance to colistin. We investigated three pairs of colistin-susceptible and colistin-resistant A. baumannii, sequentially isolated from three patients before and after colistin treatment, respectively. The pmrA and pmrB genes were sequenced by Sanger method. Amino acidic positions and their effect on protein were predicted by InterPro and PROVEAN tools. Expression of pmrA, pmrB and pmrC genes was assessed by semi-quantitative reverse transcription-PCR (qRT-PCR). We found three different nonsynonymous substitutions P233T, E301G and L168K in pmrB coding region, each one in a different colistin resistance strain. The E301G and L168K substitutions represent novel mutations in pmrB, not previously described. Relative expression of pmrA, pmrB and pmrC mRNA increased in all colistin resistant strains. In our study, pmrB substitutions were associated with pmrC over-expression and colistin resistance. Further studies are necessary to understand their impact on modification of lipid A components.
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Affiliation(s)
- Vito Marano
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Nadia Marascio
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy.
| | - Grazia Pavia
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Angelo G Lamberti
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Angela Quirino
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Rosanna Musarella
- Institute for Experimental Veterinary Medicine of Southern Italy, 88100, Catanzaro, Italy
| | - Francesco Casalinuovo
- Institute for Experimental Veterinary Medicine of Southern Italy, 88100, Catanzaro, Italy
| | - Maria Mazzitelli
- Department of Medical and Surgical Sciences, Unit of Infectious and Tropical Diseases, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Enrico M Trecarichi
- Department of Medical and Surgical Sciences, Unit of Infectious and Tropical Diseases, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Carlo Torti
- Department of Medical and Surgical Sciences, Unit of Infectious and Tropical Diseases, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Giovanni Matera
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
| | - Maria Carla Liberto
- Department of Health Sciences, Unit of Clinical Microbiology, "Magna Graecia" University, 88100, Catanzaro, Italy
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16
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Lytic transglycosylase contributes to the survival of lipooligosaccharide-deficient, colistin-dependent Acinetobacter baumannii. Clin Microbiol Infect 2019; 25:1156.e1-1156.e7. [DOI: 10.1016/j.cmi.2019.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/02/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022]
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17
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Ko KS. Antibiotic-resistant clones in Gram-negative pathogens: presence of global clones in Korea. J Microbiol 2018; 57:195-202. [PMID: 30552629 DOI: 10.1007/s12275-019-8491-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/01/2018] [Accepted: 10/02/2018] [Indexed: 12/26/2022]
Abstract
Antibiotic resistance is a global concern in public health. Antibiotic-resistant clones can spread nationally, internationally, and globally. This review considers representative antibiotic-resistant Gram-negative bacterial clones-CTX-M- 15-producing ST131 in Escherichia coli, extended-spectrum ß-lactamase-producing ST11 and KPC-producing ST258 in Klebsiella pneumoniae, IMP-6-producing, carbapenem-resistant ST235 in Pseudomonas aeruginosa, and OXA-23-producing global clone 2 in Acinetobacter baumannii-that have disseminated worldwide, including in Korea. The findings highlight the urgency for systematic monitoring and international cooperation to suppress the emergence and propagation of antibiotic resistance.
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Affiliation(s)
- Kwan Soo Ko
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
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