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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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Hirai J, Asai N, Hagihara M, Kishino T, Kato H, Sakanashi D, Ohashi W, Mikamo H. Comparative Effectiveness of Ampicillin/Sulbactam versus Cefazolin as Targeted Therapy for Bacteremia Caused by Beta-Lactamase-Producing Methicillin-Sensitive Staphylococcus aureus: A Single-Center Retrospective Study. Antibiotics (Basel) 2022; 11:1505. [PMID: 36358161 PMCID: PMC9686817 DOI: 10.3390/antibiotics11111505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 02/06/2024] Open
Abstract
Cefazolin (CFZ) is the first-line treatment for beta-lactamase-producing methicillin-sensitive Staphylococcus aureus (BP-MSSA) infection. In 2019, Japan experienced a CFZ shortage because of foreign object inclusion in a batch. Ampicillin/sulbactam (SAM) was preferred in many cases as definitive therapy for the treatment of BP-MSSA bacteremia to preserve broad-spectrum antibiotic stock. However, there are no previous studies reporting the clinical efficacy of SAM for BP-MSSA bacteremia. We aimed to compare the clinical efficacy and adverse effects of SAM versus CFZ in patients with BP-MSSA bacteremia. In total, 41 and 30 patients treated with SAM and CFZ, respectively, were identified. The baseline characteristics were similar in both groups. No significant differences were observed in length of hospital stay and all 30-day mortality between the two groups (p = 0.270 and 0.643, respectively). Moreover, no intergroup difference in 90-day mortality was found (hazard ratio 1.02, 95% confidential interval 0.227-4.53). Adverse effects, such as liver dysfunction, were less in the CFZ group than in the SAM group (p = 0.030). Therefore, in cases of poor CFZ supply or in patients allergic to CFZ and penicillinase-stable penicillins, SAM can be an effective therapeutic option for bacteremia due to BP-MSSA with attention of adverse effects, such as liver dysfunction.
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Affiliation(s)
- Jun Hirai
- Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Nagakute 480-1103, Japan
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Nagakute 480-1103, Japan
| | - Nobuhiro Asai
- Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Nagakute 480-1103, Japan
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Nagakute 480-1103, Japan
| | - Mao Hagihara
- Department of Molecular Epidemiology and Biomedical Sciences, Aichi Medical University, Nagakute 480-1103, Japan
| | - Takaaki Kishino
- Department of Emergency and Critical Care Medicine, Aichi Medical University Hospital, Nagakute 480-1103, Japan
| | - Hideo Kato
- Department of Pharmacy, Mie University Hospital, Tsu 514-8507, Japan
| | - Daisuke Sakanashi
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Nagakute 480-1103, Japan
| | - Wataru Ohashi
- Division of Biostatistics, Clinical Research Center, Aichi Medical University, Nagakute 480-1103, Japan
| | - Hiroshige Mikamo
- Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Nagakute 480-1103, Japan
- Department of Infection Control and Prevention, Aichi Medical University Hospital, Nagakute 480-1103, Japan
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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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Ngoi ST, Muhamad AN, Teh CSJ, Chong CW, Abdul Jabar K, Chai LC, Leong KC, Tee LH, AbuBakar S. β-Lactam Resistance in Upper Respiratory Tract Pathogens Isolated from a Tertiary Hospital in Malaysia. Pathogens 2021; 10:pathogens10121602. [PMID: 34959557 PMCID: PMC8705930 DOI: 10.3390/pathogens10121602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
The rise of antimicrobial resistance (AMR) among clinically important bacteria, including respiratory pathogens, is a growing concern for public health worldwide. Common causative bacteria for upper respiratory tract infections (URTIs) include Streptococcus pneumoniae and Haemophilus influenzae, and sometimes Staphylococcus aureus. We assessed the β-lactam resistant trends and mechanisms of 150 URTI strains isolated in a tertiary care hospital in Kuala Lumpur Malaysia. High rates of non-susceptibility to penicillin G (38%), amoxicillin-clavulanate (48%), imipenem (60%), and meropenem (56%) were observed in S. pneumoniae. Frequent mutations at STMK and SRNVP motifs in PBP1a (41%), SSNT motif in PBP2b (32%), and STMK and LKSG motifs in PBP2x (41%) were observed in S. pneumoniae. H. influenzae remained highly susceptible to most β-lactams, except for ampicillin. Approximately half of the ampicillin non-susceptible H. influenzae harboured PBP3 mutations (56%) and only blaTEM was detected in the ampicillin-resistant strains (47%). Methicillin-susceptible S. aureus (MSSA) strains were mostly resistant to penicillin G (92%), with at least two-fold higher median minimum inhibitory concentrations (MIC) for all penicillin antibiotics (except ticarcillin) compared to S. pneumoniae and H. influenzae. Almost all URTI strains (88-100%) were susceptible to cefcapene and flomoxef. Overall, β-lactam antibiotics except penicillins remained largely effective against URTI pathogens in this region.
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Affiliation(s)
- Soo Tein Ngoi
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia; (S.T.N.); (A.N.M.); (K.A.J.); (S.A.)
| | - Anis Najwa Muhamad
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia; (S.T.N.); (A.N.M.); (K.A.J.); (S.A.)
| | - Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia; (S.T.N.); (A.N.M.); (K.A.J.); (S.A.)
- Correspondence: ; Tel.: +603-79676674
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Bandar Sunway 47500, Malaysia;
| | - Kartini Abdul Jabar
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia; (S.T.N.); (A.N.M.); (K.A.J.); (S.A.)
| | - Lay Ching Chai
- Faculty of Science, Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur 50603, Malaysia;
| | - Kin Chong Leong
- Shionogi Singapore Pte Ltd., Anson Road, #34-14 International Plaza, Singapore 079903, Singapore; (K.C.L.); (L.H.T.)
| | - Loong Hua Tee
- Shionogi Singapore Pte Ltd., Anson Road, #34-14 International Plaza, Singapore 079903, Singapore; (K.C.L.); (L.H.T.)
| | - Sazaly AbuBakar
- Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia; (S.T.N.); (A.N.M.); (K.A.J.); (S.A.)
- Tropical Infectious Diseases Research and Education Centre (TIDREC), Universiti Malaya, Kuala Lumpur 50603, Malaysia
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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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Abstract
The phenomenon of attenuated antibacterial activity at inocula above those utilized for susceptibility testing is referred to as the inoculum effect. Although the inoculum effect has been reported for several decades, it is currently debatable whether the inoculum effect is clinically significant. The aim of the present review was to consolidate currently available evidence to summarize which β-lactam drug classes demonstrate an inoculum effect against specific bacterial pathogens. Review of the literature showed that the majority of studies that evaluated the inoculum effect of β-lactams were in vitro investigations of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Haemophilus influenzae and Staphylococcus aureus. Across all five pathogens, cephalosporins consistently displayed observable inoculum effects in vitro, whereas carbapenems were less susceptible to an inoculum effect. A handful of animal studies were available that validated that the in vitro inoculum effect translates into attenuated pharmacodynamics of β-lactams in vivo. Only a few clinical investigations were available and suggested that an in vitro inoculum effect of cefazolin against MSSA may correspond to an increased likeliness of adverse clinical outcomes in patients receiving cefazolin for bacteraemia. The presence of β-lactamase enzymes was the primary mechanism responsible for an inoculum effect, but the observation of an inoculum effect in multiple pathogens lacking β-lactamase enzymes indicates that there are likely multiple mechanisms that may result in an inoculum effect. Further clinical studies are needed to better define whether interventions made in the clinic in response to organisms displaying an in vitro inoculum effect will optimize clinical outcomes.
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Affiliation(s)
- Justin R Lenhard
- California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Zackery P Bulman
- College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
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Novel Insights into the Classification of Staphylococcal β-Lactamases in Relation to the Cefazolin Inoculum Effect. Antimicrob Agents Chemother 2020; 64:AAC.02511-19. [PMID: 32071048 DOI: 10.1128/aac.02511-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 02/10/2020] [Indexed: 12/19/2022] Open
Abstract
Cefazolin has become a prominent therapy for methicillin-susceptible Staphylococcus aureus (MSSA) infections. However, an important concern is the cefazolin inoculum effect (CzIE), a phenomenon mediated by staphylococcal β-lactamases. Four variants of staphylococcal β-lactamases have been described based on serological methodologies and limited sequence information. Here, we sought to reassess the classification of staphylococcal β-lactamases and their correlation with the CzIE. We included a large collection of 690 contemporary bloodstream MSSA isolates recovered from Latin America, a region with a high prevalence of the CzIE. We determined cefazolin MICs at standard and high inoculums by broth microdilution. Whole-genome sequencing was performed to classify the β-lactamase in each isolate based on the predicted full sequence of BlaZ. We used the classical schemes for β-lactamase classification and compared it to BlaZ allotypes found in unique sequences using the genomic information. Phylogenetic analyses were performed based on the BlaZ and core-genome sequences. The overall prevalence of the CzIE was 40%. Among 641 genomes, type C was the most predominant β-lactamase (37%), followed by type A (33%). We found 29 allotypes and 43 different substitutions in BlaZ. A single allotype, designated BlaZ-2, showed a robust and statistically significant association with the CzIE. Two other allotypes (BlaZ-3 and BlaZ-5) were associated with a lack of the CzIE. Three amino acid substitutions (A9V, E112A, and G145E) showed statistically significant association with the CzIE (P = <0.01). CC30 was the predominant clone among isolates displaying the CzIE. Thus, we provide a novel approach to the classification of the staphylococcal β-lactamases with the potential to more accurately identify MSSA strains exhibiting the CzIE.
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Weis S, Kesselmeier M, Davis JS, Morris AM, Lee S, Scherag A, Hagel S, Pletz MW. Cefazolin versus anti-staphylococcal penicillins for the treatment of patients with Staphylococcus aureus bacteraemia. Clin Microbiol Infect 2019; 25:818-827. [PMID: 30928559 DOI: 10.1016/j.cmi.2019.03.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 03/02/2019] [Accepted: 03/09/2019] [Indexed: 01/20/2023]
Abstract
BACKGROUND For patients with bacteraemia caused by methicillin-sensitive Staphylococcus aureus anti-staphylococcal penicillins (ASPs) or cefazolin are agents of choice. While ASPs are potentially nephrotoxic, cefazolin may be less effective in some S. aureus strains due to an inoculum effect. OBJECTIVES To perform a systematic literature review and meta-analysis assessing current evidence comparing cefazolin with ASPs for patients with S. aureus bacteraemia (SAB). METHODS We searched MEDLINE, ISI Web of Science (Science Citation Index Expanded) and the Cochrane Database as well as clinicaltrials.gov from inception to 26 June 2018. All studies investigating the effects of cefazolin versus ASP in patients with methicillin-sensitive SAB were eligible for inclusion regardless of study design, publication status or language. Additional information was requested by direct author contact. A meta-analysis to estimate relative risks (RRs) with the corresponding 95% confidence intervals (CIs) was performed. Statistical heterogeneity was estimated using I2. The primary endpoint was 90-day all-cause mortality. The Newcastle-Ottawa Scale (NOS) and Grading of Recommendations Assessment, Development and Evaluation (GRADE) were used for study and data quality assessment. RESULTS Fourteen non-randomized studies were included. Seven reported the primary endpoint (RR 0.71 (0.50, 1.02), low quality of evidence). Cefazolin treatment may be associated with lower 30-day mortality rates (RR 0.70 (0.54, 0.91), low quality of evidence) and less nephrotoxicity (RR 0.36 (0.21, 0.59), (low quality of evidence)). We are uncertain whether cefazolin and ASP differ regarding treatment failure/relapse as the quality of the evidence has been assessed as very low (RR of 0.84 (0.59, 1.18)). For patients with endocarditis (RR 0.71 (0.12, 4.05)) or abscesses (RR 1.17 (0.30, 4.63)), cefazolin treatment may be associated with equal 30-day and 90-day mortality (low quality of evidence). CONCLUSIONS Cefazolin seemed to be at least equally as effective as ASPs while being associated with less nephrotoxicity.
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Affiliation(s)
- S Weis
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Jena, Germany.
| | - M Kesselmeier
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Research Group Clinical Epidemiology, CSCC, Jena University Hospital, Jena, Germany
| | - J S Davis
- Global and Tropical Health Division, Menzies School of Health Research, Darwin, NT, Australia; Department of Infectious Diseases, John Hunter Hospital, Newcastle, NSW, Australia
| | - A M Morris
- Department of Medicine, Division of Infectious Diseases, Sinai Health System, University Health Network, University of Toronto, Canada
| | - S Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Republic of Korea
| | - A Scherag
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Research Group Clinical Epidemiology, CSCC, Jena University Hospital, Jena, Germany; Institute of Medical Statistics, Computer and Data Sciences, Jena University Hospital, Jena, Germany
| | - S Hagel
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - M W Pletz
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
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11
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High-Dosage Cefazolin Achieves Sufficient Cerebrospinal Diffusion To Treat an External Ventricular Drainage-Related Staphylococcus aureus Ventriculitis. Antimicrob Agents Chemother 2019; 63:AAC.01844-18. [PMID: 30420481 DOI: 10.1128/aac.01844-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/01/2018] [Indexed: 11/20/2022] Open
Abstract
A patient received continuous infusion of cefazolin 10 g then 8 g daily for an external ventricular drainage-related methicillin-susceptible Staphylococcus aureus (MSSA) ventriculitis. Median free concentrations in the cerebrospinal fluid were 11.9 and 6.1 mg/liter after 10- and 8-g doses, respectively. Free concentrations in the cerebrospinal fluid were always above the MIC usually displayed by methicillin-susceptible Staphylococcus aureus (MSSA) isolates. These results support the use of high-dose cefazolin to achieve sufficient meningeal concentrations.
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12
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Song KH, Jung SI, Lee S, Park S, Kim ES, Park KH, Park WB, Choe PG, Kim YK, Kwak YG, Kim YS, Jang HC, Kiem S, Kim HI, Kim HB. Inoculum effect of methicillin-susceptible Staphylococcus aureus against broad-spectrum beta-lactam antibiotics. Eur J Clin Microbiol Infect Dis 2018; 38:67-74. [PMID: 30269181 DOI: 10.1007/s10096-018-3392-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 09/21/2018] [Indexed: 11/29/2022]
Abstract
Scarce information concerning the inoculum effect (InE) of methicillin-susceptible Staphylococcus aureus (MSSA) against broad-spectrum β-lactam antibiotics is available. We investigated the InE of MSSA against ceftriaxone, cefepime, meropenem, ampicillin/sulbactam and piperacillin/tazobactam. The bacteraemic MSSA isolates were collected at ten Korean general hospitals from Sep 2013 to Mar 2015. The InE was defined if MICs of antibiotics at high inoculum (HI, ~5 × 107 CFU/ml) increased beyond the susceptible range compared to those at standard inoculum (SI, ~5 × 105 CFU/ml). All isolates were sequenced for blaZ gene typing. Among 302 MSSA isolates, 254 (84.1%) were positive for blaZ; types A, B, C and D were 13.6%, 26.8%, 43.4% and 0.3%, respectively. Mean HI MICs of all tested antibiotics were significantly increased and increases in HI MIC of piperacillin/tazobactam (HI, 48.14 ± 4.08 vs. SI, 2.04 ± 0.08 mg/L, p < 0.001) and ampicillin/sulbactam (HI, 24.15 ± 1.27 vs. SI, 2.79 ± 0.11 mg/L, p < 0.001) were most prominent. No MSSA isolates exhibited meropenem InE, and few isolates exhibited cefepime (0.3%) and ceftriaxone (2.3%) InE, whereas 43.0% and 65.9% of MSSA isolates exhibited piperacillin/tazobactam and ampicillin/sulbactam InE, respectively. About 93% of type C blaZ versus 45% of non-type C exhibited ampicillin/sulbactam InE (p < 0.001) and 88% of type C blaZ versus 9% of non-type C exhibited piperacillin/tazobactam InE (p < 0.001). A large proportion of MSSA clinical isolates, especially those positive for type C blaZ, showed marked ampicillin/sulbactam InE and piperacillin/tazobactam.
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Affiliation(s)
- Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Sook-In Jung
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Shinwon Lee
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea.
| | - Sohee Park
- Department of Internal Medicine, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, 179 Gudeok-ro, Seo-gu, Busan, 49241, Republic of Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Kyung-Hwa Park
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Wan Beom Park
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Pyoeng Gyun Choe
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Young Keun Kim
- Department of Internal Medicine, Yonsei University Medical School, Wonju, Republic of Korea
| | - Yee Gyung Kwak
- Department of Internal Medicine, Inje University Ilsan Paik Hospital, Goyang, Republic of Korea
| | - Yeon-Sook Kim
- Division of Infectious Diseases, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, Republic of Korea
| | - Hee-Chang Jang
- Department of Internal Medicine, Chonnam National University Hwasun Hospital, Hwasun, Jeollanam-do, Republic of Korea
| | - Sungmin Kiem
- Department of Internal Medicine, Inje University College of Medicine, Busan, Republic of Korea
| | - Hye-In Kim
- Department of Internal Medicine, Daegu Fatima Hospital, Daegu, Republic of Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
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