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Tsuji S, Gotoh K, Manabe T, Iio K, Fukushima S, Matsushita O, Hagiya H. Cefazolin inoculum effect in methicillin-susceptible Staphylococcus aureus clinical isolates. Diagn Microbiol Infect Dis 2024; 110:116399. [PMID: 38875894 DOI: 10.1016/j.diagmicrobio.2024.116399] [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: 04/04/2024] [Revised: 06/03/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024]
Abstract
We investigated the prevalence and characteristics of Cefazolin inoculum effect (CInE) among clinical MSSA isolates in Japan. Although 35.5 % (39 isolates) were positive for the blaZ gene, none met the phenotypic criteria for CInE. Our findings suggested a very low prevalence of CInE among MSSA isolates in our clinical setting.
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Affiliation(s)
- Shuma Tsuji
- Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Department of Medical Laboratory Science, Okayama University Graduate School of Health Sciences, Okayama, Japan
| | - Kazuyoshi Gotoh
- Department of Medical Laboratory Science, Okayama University Graduate School of Health Sciences, Okayama, Japan
| | - Tadahiro Manabe
- Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Koji Iio
- Microbiology Division, Clinical Laboratory, Okayama University Hospital, Okayama, Japan
| | - Shinnosuke Fukushima
- Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Osamu Matsushita
- Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hideharu Hagiya
- Department of Infectious Diseases, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
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Lo CKF, Sritharan A, Zhang J, Li N, Zhang C, Wang F, Loeb M, Bai AD. Clinical significance of cefazolin inoculum effect in serious MSSA infections: a systematic review. JAC Antimicrob Resist 2024; 6:dlae069. [PMID: 38716403 PMCID: PMC11073751 DOI: 10.1093/jacamr/dlae069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/10/2024] [Indexed: 06/29/2024] Open
Abstract
Background The cefazolin inoculum effect (CzIE) is a phenomenon whereby some MSSA isolates demonstrate resistance to cefazolin when a high bacterial inoculum is used for susceptibility testing. The clinical significance of this phenotypic phenomenon remains unclear. We conducted a systematic review to answer the following question: In patients with serious MSSA infection treated with cefazolin, does infection due to CzIE-positive MSSA isolates result in worse clinical outcomes than infection due to CzIE-negative MSSA isolates? Methods Ovid MEDLINE, Embase, Cochrane CENTRAL, medRxiv and bioRxiv were searched from inception until 12 April 2023. Studies were included if they tested for CzIE in clinical isolates from MSSA infections in humans. Two independent reviewers extracted data and conducted risk-of-bias assessment. Main outcomes were treatment failure and mortality. Pooling of study estimates was not performed given the heterogeneity of patient populations and outcome definitions. Results Twenty-three observational studies were included. CzIE presence amidst MSSA isolates ranged from 0% to 55%. There was no statistically significant mortality difference in two studies that compared MSSA infections with and without CzIE, with ORs ranging from 0.72 to 19.78. Of four studies comparing treatment failure, ORs ranged from 0.26 to 13.00. One study showed a significantly higher treatment failure for the CzIE group, but it did not adjust for potential confounders. Conclusions The evidence on CzIE is limited by small observational studies. In these studies, CzIE did not predict higher mortality in MSSA infections treated with cefazolin. Our findings do not support CzIE testing in clinical practice currently.
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Affiliation(s)
- Calvin Ka-Fung Lo
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Ashwin Sritharan
- Michael G. DeGroote Undergraduate School of Medicine, McMaster University, Hamilton, ON, Canada
| | - Jiesi Zhang
- Faculty of Health Sciences, Queen’s University, Kingston, ON, Canada
| | - Nicole Li
- Faculty of Arts and Sciences, Queen's University, Kingston, ON, Canada
| | - Cindy Zhang
- Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Frank Wang
- Michael G. DeGroote Undergraduate School of Medicine, McMaster University, Hamilton, ON, Canada
| | - Mark Loeb
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Anthony D Bai
- Division of Infectious Diseases, Department of Medicine, Queen’s University, Kingston, ON, Canada
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Svishchuk J, Ebbert K, Waddell B, Izydorczyk C, Acosta N, Somayaji R, Rabin HR, Bjornson CL, Lisboa L, Gregson DB, Conly JM, Surette MG, Parkins MD. Epidemiology and impact of methicillin-sensitive Staphylococcus aureus with β-lactam antibiotic inoculum effects in adults with cystic fibrosis. Antimicrob Agents Chemother 2023; 67:e0013623. [PMID: 37966229 PMCID: PMC10720481 DOI: 10.1128/aac.00136-23] [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: 01/31/2023] [Accepted: 08/22/2023] [Indexed: 11/16/2023] Open
Abstract
Staphylococcus aureus is the most prevalent cystic fibrosis (CF) pathogen. Several phenotypes are associated with worsened CF clinical outcomes including methicillin-resistance and small-colony-variants. The inoculum effect (IE) is characterized by reduced β-lactam susceptibility when assessed at high inoculum. The IE associates with worse outcomes in bacteremia and other high-density infections, and may therefore be relevant to CF. The prevalence of IE amongst a CF cohort (age ≥18 years), followed from 2013 to 2016, was investigated. Yearly methicillin-sensitive S. aureus (MSSA) isolates were screened at standard (5 × 105 CFU/mL) and high (5 × 107 CFU/mL) inoculum against narrow-spectrum anti-Staphylococcal β-lactams and those with anti-pseudomonal activity common to CF. A ≥ 4-fold increase in minimum inhibitory concentration between standard and high inoculum defined IE. Isolates underwent blaZ sequencing and genotyping and were compared against published genomes. Fifty-six percent (99/177) of individuals had MSSA infection. MSSA was observed at ≥105 CFU/mL in 44.8% of entry sputum samples. The prevalence of the IE was 25.0%-cefazolin; 13.5%-cloxacillin; 0%-meropenem; 1.0%-cefepime; 5.2%-ceftazidime; and 34.4%-piperacillin-tazobactam amongst baseline MSSA isolates assessed. blaZ A associated with cefazolin IE (P = 0.0011), whereas blaZ C associated with piperacillin-tazobactam IE (P < 0.0001). Baseline demographics did not reveal specific risk factors for IE-associated infections, nor were long-term outcomes different. Herein, we observed the IE in CF-derived MSSA disproportionally for cefazolin and piperacillin-tazobactam and this phenotype strongly associated with underlying blaZ genotype. The confirmation of CF being a high density infection, and the identification of high prevalence of MSSA with IE in CF supports the need for prospective pulmonary exacerbation treatment studies to understand the impact of this phenotype.
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Affiliation(s)
- J. Svishchuk
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - K. Ebbert
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - B. Waddell
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - C. Izydorczyk
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - N. Acosta
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - R. Somayaji
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - H. R. Rabin
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - C. L. Bjornson
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - L. Lisboa
- Department of Pathology and Laboratory Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - D. B. Gregson
- Department of Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - J. M. Conly
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
- Department of Pathology and Laboratory Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - M. G. Surette
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - M. D. Parkins
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
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George CRR, Lahra MM, Nguyen T, Gatus B. Disc Test for Detecting Staphylococcus aureus Strains Producing Type A and Type C β-Lactamases. Microbiol Spectr 2023; 11:e0022023. [PMID: 37409947 PMCID: PMC10434206 DOI: 10.1128/spectrum.00220-23] [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: 01/15/2023] [Accepted: 05/22/2023] [Indexed: 07/07/2023] Open
Abstract
Staphylococcus aureus can produce β-lactamases capable of hydrolyzing penicillins and first-generation cephalosporins. The propensity of type A and type C β-lactamase-producing S. aureus (TAPSA and TCPSA) to hydrolyze cefazolin at a high inoculum is termed the cefazolin inoculum effect (CIE). Strains with a CIE have a theoretical risk of causing treatment failure and are unable to be detected routinely by most laboratories. We developed a high-performing yet straightforward β-lactamase disc test that identifies and differentiates both TAPSA and TCPSA and is suitable for routine diagnostic laboratory workflows. Clinical isolates of S. aureus resistant to penicillin were identified, and their blaZ genes were sequenced. MICs were determined at low and high inocula (5 × 105 CFU/mL and 5 × 107 CFU/mL), and isolates demonstrating a CIE were characterized. A semimechanistic model was established to describe differential hydrolysis patterns, and candidate models were iteratively assessed using area-under-the-curve analysis from competitor receiver operating characteristic (ROC) curves. Biomarker thresholds were derived from Youdon index-derived optimal cutoff values. Genetic analysis of 99 isolates identified 26 TAPSA isolates and 45 TCPSA isolates. The model best differentiating TAPSA from non-TAPSA utilized cefazolin-to-cephalothin ratio analysis (sensitivity, 96.2%; specificity, 98.6%). The model best differentiating TCPSA from non-TCPSA incorporated cefazolin, cephalothin, and oxacillin (sensitivity, 88.6%; specificity, 96.6%). TAPSA and TCPSA can be differentiated using three antibiotic discs on a single agar plate. The test has potential value in typing the β-lactamase type from isolates from patients that are candidates for or have failed cefazolin therapy. IMPORTANCE The key significance of this article is that it details a straightforward method of performing a disc test that can differentiate Staphylococcus aureus isolates that are likely to be associated with a cefazolin inoculum effect and theoretical risk of cefazolin treatment failure from isolates that are less likely to be associated with a cefazolin inoculum effect.
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Affiliation(s)
- C. R. Robert George
- NSW Health Pathology, Microbiology, John Hunter Hospital, Newcastle, Australia
| | - Monica M. Lahra
- NSW Health Pathology, Microbiology, Prince of Wales Hospital, Randwick, Australia
- School of Medical Sciences, Faculty of Medicine, the University of New South Wales, Sydney, Australia
| | - Thanh Nguyen
- NSW Health Pathology, Microbiology, Prince of Wales Hospital, Randwick, Australia
| | - Barrie Gatus
- NSW Health Pathology, Microbiology, Prince of Wales Hospital, Randwick, Australia
- School of Medical Sciences, Faculty of Medicine, the University of New South Wales, Sydney, Australia
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Bourreau A, Le Mabecque V, Broquet A, Caillon J. Prevalence of a cefazolin inoculum effect associated with blaZ gene types, and clinical outcomes among methicillin-susceptible Staphylococcus aureus blood isolates of patients with infective endocarditis. Infect Dis Now 2023; 53:104626. [PMID: 36184048 DOI: 10.1016/j.idnow.2022.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/21/2022] [Accepted: 09/23/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVES A proportion of blaZ gene-positive methicillin-susceptible Staphylococcus aureus (MSSA) strains exhibits the cefazolin inoculum effect (CInE). Its clinical impact remains uncertain but could compromise the use of cefazolin in high-burden infections. To date, no study has been conducted in France or in Europe. We aimed to assess the prevalence of CInE and its association with blaZ beta-lactamase and S. aureus protein A (spa) types, and to assess the clinical outcomes in cefazolin-treated patients for infective endocarditis whose strain exhibited a CInE. METHODS This was a French single-center retrospective study of 51 MSSA strains from patients of the Nantes endocarditis prospective cohort, conducted between 2013 and 2018. RESULTS Cefazolin MIC50 at high inoculum was 2 mg/L (IQR 1-2). CInE was found in 17.6 % of tested strains. Among blaZ-positive strains (n = 44), type A beta-lactamase was predominant (n = 25, 57 %). Thirty-seven S. aureus protein A (spa) types were found. No statistical association was shown between blaZ or spa types and CInE. CInE was neither associated with a higher rate of persistent bacteremia (25 % vs 56.3 %, p = 0.58) nor with clinical failure in patients treated with cefazolin, in comparison to patients with no CInE strain (25 % vs 56.3 %, p = 0.58). CONCLUSION The cefazolin inoculum effect was found in a substantial number of Staphylococcus aureus strains; however, minimum inhibitory concentrations remained globally low. CInE was not associated with a higher proportion of clinical failure on treatment.
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Affiliation(s)
- A Bourreau
- Department of Infectious Diseases, Nantes, France; Centre d'Investigation Clinique, Unité d'Investigation Clinique 1413 INSERM, CHU Nantes, Nantes, France.
| | - V Le Mabecque
- Institut de RechercheenSanté de l'Université de Nantes, EA 3826-Thérapeutiques cliniques et expérimentales des infections, France
| | - A Broquet
- Institut de RechercheenSanté de l'Université de Nantes, EA 3826-Thérapeutiques cliniques et expérimentales des infections, France
| | - J Caillon
- Department of Bacteriology, CHU Hôtel-Dieu, Nantes, France
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Coombs GW, Yee NWT, Daley D, Bennett CM, Robinson JO, Stegger M, Shoby P, Mowlaboccus S. Molecular Epidemiology of Penicillin-Susceptible Staphylococcus aureus Bacteremia in Australia and Reliability of Diagnostic Phenotypic Susceptibility Methods to Detect Penicillin Susceptibility. Microorganisms 2022; 10:microorganisms10081650. [PMID: 36014068 PMCID: PMC9413241 DOI: 10.3390/microorganisms10081650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/29/2022] Open
Abstract
Background: Defined by the emergence of antibiotic resistant strains, Staphylococcus aureus is a priority bacterial species with high antibiotic resistance. However, a rise in the prevalence of penicillin-susceptible S. aureus (PSSA) bloodstream infections has recently been observed worldwide, including in Australia, where the proportion of methicillin-susceptible S. aureus causing bacteremia identified phenotypically as penicillin-susceptible has increased by over 35%, from 17.5% in 2013 to 23.7% in 2020. Objectives: To determine the population structure of PSSA causing community- and hospital-onset bacteremia in Australia and to evaluate routine phenotypic antimicrobial susceptibility methods to reliably confirm penicillin resistance on blaZ-positive S. aureus initially classified as penicillin-susceptible by the Vitek® 2 automated microbiology system. Results: Whole genome sequencing on 470 PSSA collected in the 2020 Australian Group on Antimicrobial Resistance Australian Staphylococcus aureus Sepsis Outcome Programme identified 84 multilocus sequence types (STs), of which 79 (463 isolates) were grouped into 22 clonal complexes (CCs). The dominant CCs included CC5 (31.9%), CC97 (10.2%), CC45 (10.0%), CC15 (8.7%), and CC188 (4.9%). Many of the CCs had multiple STs and spa types and, based on the immune evasion cluster type, isolates within a CC could be classified into different strains harboring a range of virulence and resistance genes. Phylogenetic analyses of the isolates showed most CCs were represented by one clade. The blaZ gene was identified in 45 (9.6%) PSSA. Although multiclonal, approximately 50% of blaZ-positive PSSA were from CC15 and were found to be genetically distant from the blaZ-negative CC15 PSSA. The broth microdilution, Etest® and cefinase, performed poorly; however, when the appearance of the zone edge was considered; as per the EUCAST and CLSI criteria, disc diffusion detected 100% of blaZ-positive PSSA. Conclusions: In Australia, PSSA bacteremia is not caused by the expansion of a single clone. Approximately 10% of S. aureus classified as penicillin-susceptible by the Vitek® 2 harbored blaZ. Consequently, we recommend that confirmation of Vitek® 2 PSSA be performed using an alternative method, such as disc diffusion with careful interpretation of the zone edge.
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Affiliation(s)
- Geoffrey W. Coombs
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
- Department of Microbiology, PathWest Laboratory Medicine-WA, Fiona Stanley Hospital, Murdoch, WA 6150, Australia
| | - Nicholas W. T. Yee
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
| | - Denise Daley
- Department of Microbiology, PathWest Laboratory Medicine-WA, Fiona Stanley Hospital, Murdoch, WA 6150, Australia
| | - Catherine M. Bennett
- Institute of Health Transformation, Deakin University, Melbourne, VIC 3125, Australia
| | - James O. Robinson
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
- Department of Microbiology, PathWest Laboratory Medicine-WA, Fiona Stanley Hospital, Murdoch, WA 6150, Australia
- Department of Infectious Diseases, Fiona Stanley Hospital, Murdoch, WA 6150, Australia
- Department of Infectious Diseases, Royal Perth Hospital, Perth, WA 6003, Australia
| | - Marc Stegger
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
- Department of Bacteria, Parasites and Fungi, Statens Serum Institute, 2300 Copenhagen, Denmark
| | - Princy Shoby
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
| | - Shakeel Mowlaboccus
- Antimicrobial Resistance and Infectious Diseases (AMRID) Research Laboratory, Murdoch University, Murdoch, WA 6150, Australia
- Department of Microbiology, PathWest Laboratory Medicine-WA, Fiona Stanley Hospital, Murdoch, WA 6150, Australia
- School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia
- Correspondence:
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Prevalence and Characterization of the Cefazolin Inoculum Effect in North American Methicillin-Susceptible Staphylococcus aureus Isolates. J Clin Microbiol 2022; 60:e0249521. [PMID: 35578988 PMCID: PMC9297818 DOI: 10.1128/jcm.02495-21] [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: 02/03/2023] Open
Abstract
Antistaphylococcal penicillins and cefazolin remain the primary treatments for infections with methicillin-susceptible Staphylococcus aureus (MSSA). The cefazolin inoculum effect (CzIE) causes the cefazolin MIC to be elevated in proportion to the number of bacteria in the inoculum. The objective of this multicenter study was to evaluate the prevalence of the CzIE in North American MSSA isolates. Clinical MSSA isolates from six microbiology laboratories in the United States and one microbiology laboratory in Canada were screened for the CzIE by broth microdilution at a standard inoculum (~5 × 105 CFU/mL) and a high inoculum (~5 × 107 CFU/mL). Genome sequencing was performed to further characterize the MSSA isolates. The CzIE was present in 57/305 (18.6%) MSSA isolates, ranging from 0% to 27.9% across study sites. More of the CzIE-positive isolates (29.8%) had standard inoculum cefazolin MICs of 1.0 μg/mL than the CzIE-negative isolates did (3.2%) (P < 0.0001). Conversely, more CzIE-negative isolates (39.5%) had standard inoculum MICs of 0.25 μg/mL than the CzIE positive isolates did (5.3%) (P < 0.0001). The most common BlaZ β-lactamase types found in the CzIE-positive strains were type C (53.7%) and type A (44.4%). ST8 and ST30 were the most common sequence types among CzIE-positive isolates and correlated with BlaZ type C and A, respectively. The CzIE was present in up to a quarter of clinical MSSA isolates from North American clinical laboratories. Further studies to determine the impact of the presence of the CzIE on clinical outcomes are needed.
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Staphylococcus aureus in Non-Cystic Fibrosis Bronchiectasis: Prevalence and Genomic Basis of High Inoculum Beta-Lactam Resistance. Ann Am Thorac Soc 2022; 19:1285-1293. [PMID: 35213810 DOI: 10.1513/annalsats.202108-965oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rationale The pathobiology of Staphylococcus aureus in non-cystic fibrosis bronchiectasis (nCFB) is poorly defined. When present at high density or "inoculum", some methicillin-sensitive S. aureus (MSSA) can inefficiently degrade anti-Staphylococcal beta-lactam antibiotics via BlaZ penicillinases (termed, the inoculum effect). Given the high burden of organisms in bronchiectatic airways, this is particularly relevant. Objectives Drawing from a prospectively-collected biobank, we sought to understand the prevalence, natural history, potential for transmission, and antibiotic resistance profiles amongst nCFB-derived MSSA isolates. Methods All individuals attending a regional consultancy nCFB clinic with sputum collected between 1981-2017 were considered, and those with ≥1 S. aureus-positive culture comprised the cohort. Each individual's most recent biobank isolate was subjected to whole genome sequencing (including the blaZ gene), antibacterial susceptibility testing, and comparative beta-lactam testing at standard (5 x 105CFU/mL) and high (5 x 107CFU/mL) inoculum to assess for the inoculum, and pronounced inoculum effect (IE and pIE, respectively). Results Seventy-four of 209 (35.4%) individuals had ≥1 sputum sample(s) with S. aureus (68 MSSA, 6 MRSA). Those with S. aureus infection were more likely to be female. Amongst 60/74 MSSA isolates subjected to WGS, no evidence of transmission was identified, although specific MLST types were prevalent including ST-1, ST-15, ST-30, and ST-45. Antibiotic resistance was uncommon except for macrolides (~20%). Amongst the 60 MSSA, prevalence of IE and pIE, respectively, were observed to be drug specific; meropenem (0%, 0%), cefepime (3%, 5%), ceftazidime (8%, 0%), cloxacillin (12%, 0%), cefazolin (23%, 0%) and piperacillin-tazobactam (37%, 17%). The cefazolin IE associated with blaZ type A (p<0.01) and ST-30 (p<0.01), whereas the piperacillin-tazobactam IE associated with type C blaZ (p<0.001) and ST-15 (p<0.05). Conclusions S. aureus infection was common, although no evidence of transmission was apparent in our nCFB cohort. While routine susceptibility testing did not identify significant resistance, inoculum-related resistance was found to be relevant for commonly used nCFB antibiotics including cefazolin and piperacillin-tazobactam. Given previous associations between IEs and negative patient outcomes, further work is warranted to understand how this phenotype impacts nCFB disease progression.
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Jin Y, Zhou W, Zhan Q, Chen Y, Luo Q, Shen P, Xiao Y. Genomic epidemiology and characterisation of penicillin-sensitive Staphylococcus aureus isolates from invasive bloodstream infections in China: an increasing prevalence and higher diversity in genetic typing be revealed. Emerg Microbes Infect 2022; 11:326-336. [PMID: 34991434 PMCID: PMC8786255 DOI: 10.1080/22221751.2022.2027218] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Many countries have reported increasing rates of penicillin-susceptible methicillin-sensitive Staphylococcus aureus (MSSA-PENS). To date, there is relatively little known about the current situation and molecular characteristics of MSSA-PENS in China. In this study, we carried out a laboratory-based multi-region retrospective study to investigate the genomic epidemiology and characterisation of MSSA-PENS isolated from invasive bloodstream infections (BSIs) across 17 provinces. The prevalence of MSSA-PENS isolates increased significantly over the 6-year period, with the proportion increasing from 3.51% in 2014-8.80% in 2019, an average relative increase of 22.14% per year (95% confidence interval 9.67%-34.61%, P for trend <0.001), suggesting that China is experiencing a resurgence of MSSA-PENS. Phylogenetic analysis showed a higher strain diversity occurred; the most frequent clonal complexes (CCs) identified were CC188 (17.14%), CC398 (15.71%) and CC5 (15.71%). Over half of MSSA-PENS strains were pan-susceptible, with erythromycin the most frequent resistance observed. Moreover, 25 isolates were identified as immune evasion cluster negative, including CC15, CC188 and CC1, and 6 strains encoded the Panton-Valentine leucocidin gene. Importantly, virulence assays showed that MSSA-PENS exhibited a level of virulence comparable to that of penicillin-resistant MSSA (MSSA-PENR), indicating that more-sensitive strains should not be mistaken for lacking aggressiveness in vivo. Furthermore, 11 of these isolates were confirmed as blaZ positive but phenotype sensitive, with different amino acid changes in blaZ. Our data support the recommendation to clinicians regarding the usage of penicillin in invasive BSIs caused by MSSA-PENS, which might create a novel opportunity for better antimicrobial stewardship in the future.
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Affiliation(s)
- Ye Jin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Wangxiao Zhou
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Qing Zhan
- Infection Control Department, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Yunbo Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Qixia Luo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Ping Shen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.,Jinan Microecological Biomedicine Shandong Laboratory, Jinan, People's Republic of China
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Novak AR, Krsak M, Kiser TH, Neumann RT, Cava Prado L, Molina KC, Mueller SW. Pharmacokinetic Evaluation of Cefazolin in the Cerebrospinal Fluid of Critically Ill Patients. Open Forum Infect Dis 2021; 9:ofab649. [PMID: 35111872 PMCID: PMC8802796 DOI: 10.1093/ofid/ofab649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/24/2021] [Indexed: 11/22/2022] Open
Abstract
Background The relative distribution of cefazolin into the cerebrospinal fluid (CSF) remains debated. Determining the distribution of cefazolin into the CSF in noninfected adults may allow for further treatment applications of cefazolin. This prospective pharmacokinetic study aimed to determine the pharmacokinetic parameters of cefazolin in serum and CSF from external ventricular drains (EVDs) in neurologically injured adults. Methods Blood and CSF were collected, using a biologic waste protocol, for cefazolin quantification and trapezoidal rule–based pharmacokinetic analysis in a total of 15 critically ill adults receiving 2000 mg intravenously every 8 hours or the renal dose equivalent for EVD prophylaxis. Results A median (range) of 3 (2–4) blood and 3 (2–5) CSF samples were collected for each patient. The most common admitting diagnosis was subarachnoid hemorrhage (66.7%). The median calculated cefazolin CSF Cmax and Cmin values (interquartile range [IQR]) were 2.97 (1.76–8.56) mg/L and 1.59 (0.77–2.17) mg/L, respectively. The median (IQR) CSF to serum area under the curve ratio was 6.7% (3.7%–10.6%), with time-matched estimates providing a similar estimate (8.4%). Of those receiving cefazolin every 8 hours, the median and minimum directly measured CSF cefazolin concentration ≥4 hours following administration were 1.87 and 0.78 mg/L, respectively. Conclusions Cefazolin dosed for EVD prophylaxis achieved CSF concentrations suggesting viability as a therapeutic option for patients with meningitis or ventriculitis due to susceptible bacteria such as methicillin-susceptible Staphylococcus aureus. Further clinical trials are required to confirm a role in therapy for cefazolin. Population-based pharmacokinetic–pharmacodynamic modeling may suggest an optimal cefazolin regimen for the treatment of central nervous system infections.
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Affiliation(s)
- Alison R Novak
- Department of Pharmacy, UCHealth - University of Colorado Hospital, Aurora, Colorado, USA
| | - Martin Krsak
- Division of Infectious Diseases, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Tyree H Kiser
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Robert T Neumann
- Division of Neurosurgery, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Luis Cava Prado
- Division of Neurosurgery, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Kyle C Molina
- Department of Pharmacy, UCHealth - University of Colorado Hospital, Aurora, Colorado, USA
- Division of Infectious Diseases, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Scott W Mueller
- Department of Pharmacy, UCHealth - University of Colorado Hospital, Aurora, Colorado, USA
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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Mama OM, Aspiroz C, Lozano C, Ruiz-Ripa L, Azcona JM, Seral C, Cercenado E, López-Cerero L, Palacian P, Belles-Belles A, Berdonces P, Siller M, Aguirre-Quiñonero A, Zarazaga M, Torres C. Penicillin susceptibility among invasive MSSA infections: a multicentre study in 16 Spanish hospitals. J Antimicrob Chemother 2021; 76:2519-2527. [PMID: 34245259 DOI: 10.1093/jac/dkab208] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/25/2021] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVES To determine the prevalence of penicillin susceptibility among MSSA causing bloodstream infections (BSIs) in 16 Spanish hospitals and to characterize the penicillin-susceptible MSSA (MSSA-PENS) isolates. METHODS A total of 1011 Staphylococcus aureus isolates were collected from blood cultures in 16 Spanish hospitals during 2018-19 (6-12 months) and their susceptibility to 18 antimicrobials was determined. The MSSA-PENS isolates were selected and examined by PCR to determine the presence of the blaZ gene, other resistance genes and the genes lukF/lukS-PV, eta, etb and tst. The immune evasion cluster (IEC) type was also analysed. All the MSSA-PENS isolates were submitted to S. aureus protein A (spa) typing and the clonal complexes (CCs) were assigned according to their spa type. RESULTS The prevalence of MSSA was 74.6% (754/1011) and 14.9% (151/1011) were MSSA-PENS-blaZnegative. MSSA-PENS-blaZnegative isolates (n = 151) were ascribed to 88 spa types and 11 CCs. The most frequent CCs were CC5 (35/151) and CC398 (25/151), with t002-CC5 and t571-CC398 being the most common lineages. Pan-susceptibility was identified in 117 of the 151 MSSA-PENS-blaZnegative isolates (77.5%). In the remaining isolates, erythromycin and clindamycin resistance was the most frequent resistance found, although tobramycin, ciprofloxacin, fusidic acid, mupirocin and/or tetracycline resistance was also detected. Thirty-eight MSSA-PENS-blaZnegative isolates were IEC negative and four isolates were Panton-Valentine leucocidin ('PVL') positive. CONCLUSIONS A high penicillin susceptibility rate was detected among MSSA, opening therapeutic opportunities for BSIs. The emergence of new successful MSSA-PENS clones could be responsible for these data. The detection among MSSA-PENS-blaZnegative isolates of the clonal lineage CC398 or the absence of an IEC raises questions about their possible animal origin, requiring further analysis.
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Affiliation(s)
| | - Carmen Aspiroz
- Servicio Microbiología, Hospital Royo Villanova, Zaragoza, Spain
| | - Carmen Lozano
- Área Bioquímica y Biología Molecular, Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | - Laura Ruiz-Ripa
- Área Bioquímica y Biología Molecular, Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | | | - Cristina Seral
- Servicio Microbiología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain
| | - Emilia Cercenado
- Servicio Microbiología, Hospital General Universitario Gregorio Marañón, CIBERES, Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, Madrid, Spain
| | - Lorena López-Cerero
- Unidad de Enfermedades Infecciosas y Microbiología, Hospital Universitario Virgen Macarena, Departamento de Microbiología, Universidad de Sevilla, Instituto de Biomedicina de Sevilla, Sevilla, Spain
| | - Pilar Palacian
- Servicio Microbiología, Hospital Universitario Miguel Servet/IIS Aragón, Zaragoza, Spain
| | - Alba Belles-Belles
- Servicio Microbiología, Hospital Universitario Arnau de Vilanova, Lérida, Spain
| | | | - María Siller
- Servicio Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | | | - Myriam Zarazaga
- Área Bioquímica y Biología Molecular, Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | - Carmen Torres
- Área Bioquímica y Biología Molecular, Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, Spain
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A Test for the Rapid Detection of the Cefazolin Inoculum Effect in Methicillin-Susceptible Staphylococcus aureus. J Clin Microbiol 2021; 59:JCM.01938-20. [PMID: 33536292 DOI: 10.1128/jcm.01938-20] [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] [Received: 07/25/2020] [Accepted: 01/23/2021] [Indexed: 11/20/2022] Open
Abstract
The cefazolin inoculum effect (CzIE) has been associated with therapeutic failures and mortality in invasive methicillin-susceptible Staphylococcus aureus (MSSA) infections. A diagnostic test to detect the CzIE is not currently available. We developed a rapid (∼3 h) CzIE colorimetric test to detect staphylococcal-β-lactamase (BlaZ) activity in supernatants after ampicillin induction. The test was validated using 689 bloodstream MSSA isolates recovered from Latin America and the United States. The cefazolin MIC determination at a high inoculum (107 CFU/ml) was used as a reference standard (cutoff ≥16 μg/ml). All isolates underwent genome sequencing. A total of 257 (37.3%) of MSSA isolates exhibited the CzIE by the reference standard method. The overall sensitivity and specificity of the colorimetric test was 82.5% and 88.9%, respectively. Sensitivity in MSSA isolates harboring type A BlaZ (the most efficient enzyme against cefazolin) was 92.7% with a specificity of 87.8%. The performance of the test was lower against type B and C enzymes (sensitivities of 53.3% and 72.3%, respectively). When the reference value was set to ≥32 μg/ml, the sensitivity for isolates carrying type A enzymes was 98.2%. Specificity was 100% for MSSA lacking blaZ The overall negative predictive value ranged from 81.4% to 95.6% in Latin American countries using published prevalence rates of the CzIE. MSSA isolates from the United States were genetically diverse, with no distinguishing genomic differences from Latin American MSSA, distributed among 18 sequence types. A novel test can readily identify most MSSA isolates exhibiting the CzIE, particularly those carrying type A BlaZ. In contrast to the MIC determination using high inoculum, the rapid test is inexpensive, feasible, and easy to perform. After minor validation steps, it could be incorporated into the routine clinical laboratory workflow.
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