Ventriculitis due to a hetero strain of vancomycin intermediate Staphylococcus aureus (hVISA): successful treatment with linezolid in combination with intraventricular vancomycin

Expert consensus statement on therapeutic drug monitoring and individualization of linezolid

Linezolid is an oxazolidinone antibacterial drug, and its therapeutic drug monitoring and individualized treatment have been challenged since its approval. With the in-depth clinical research of linezolid, we have changed our attitude toward its therapeutic drug monitoring and our view of individualized treatment. On the basis of summarizing the existing clinical studies, and based on the practical experience of each expert in their respective professional fields, we have formed this expert consensus. Our team of specialists is a multidisciplinary team that includes pharmacotherapists, clinical pharmacology specialists, critical care medicine specialists, respiratory specialists, infectious disease specialists, emergency medicine specialists and more. We are committed to the safe and effective use of linezolid in patients in need, and the promotion of its therapeutic drug monitoring.

Setting priorities for ageing research in Africa: A systematic mapping review of 512 studies from sub-Saharan Africa

Background

In 2040, the older population's growth rate in sub-Saharan Africa (SSA) will be faster than those experienced by developed nations since 1950. In preparation for this growth, the National Institute on Aging commissioned the National Academies' Committee on Population to organize a workshop on advancing aging research in Africa. This meeting provided a platform for discussing some areas requiring improvement in aging research in SSA regions. We believed that conducting a systematic review of peer-reviewed articles to set priorities for aging research in SSA is warranted. Therefore, this article is the first in a Four-Part series that summaries the types and trends of peer-reviewed studies in SSA.

Methods

This systematic mapping review followed the Search-Appraisal-Synthesis-Analysis Framework. We systematically searched multiple databases from inception till February 2021 and included peer-reviewed articles conducted with/for older adults residing in SSA. Conventional content analysis was employed to categorize studies into subject-related areas.

Results

We included 512 studies (quantitative = 426, qualitative = 71 and mixed-method = 15). Studies were conducted in 32 countries. Quantitative studies included were observational studies: cross-sectional (n = 250, 59%), longitudinal (n = 126, 30%), and case-control (n = 12, 3%); and experimental studies: pre-post design (n = 4, 1%), randomized control trial (RCT, n = 12, 3%); and not reported (n = 21, 5%). Fifteen qualitative studies did not state their study design; where stated, study design ranged from descriptive (n = 14, 20%), ethnography (n = 12, 17%), grounded theory (n = 7, 10%), narrative (n = 5, 7%), phenomenology (n = 10, 14%), interpretative exploratory (n = 4, 6%), case studies (n = 4, 6%). Of the 15 mixed-method studies, seven did not state their mixed-method design. Where stated, design includes concurrent (n = 1), convergent (n = 1), cross-sectional (n = 3), informative (n = 1), sequential exploratory (n = 1) and retrospective (n = 2). Studies were classified into 30 (for quantitative studies) and seven (for qualitative and mixed-method) subject-related areas. HIV/AIDs-related and non-communicable diseases-related studies were the most predominant subject-related areas. No studies explored the transdisciplinary co-production of interventions.

Conclusions

There are glaring gaps in ageing research in SSA, especially mixed-methods and RCTs. A large number of studies focused on HIV/AIDs and non-communicable disease-related studies. National and international funding agencies should set up priority funding competitions for transdisciplinary collaborations in ageing research.

Setting priorities for ageing research in Africa: A systematic mapping review of 512 studies from sub-Saharan Africa

BACKGROUND

In 2040, the older population's growth rate in sub-Saharan Africa (SSA) will be faster than those experienced by developed nations since 1950. In preparation for this growth, the National Institute on Aging commissioned the National Academies' Committee on Population to organize a workshop on advancing aging research in Africa. This meeting provided a platform for discussing some areas requiring improvement in aging research in SSA regions. We believed that conducting a systematic review of peer-reviewed articles to set priorities for aging research in SSA is warranted. Therefore, this article is the first in a Four-Part series that summaries the types and trends of peer-reviewed studies in SSA.

METHODS

This systematic mapping review followed the Search-Appraisal-Synthesis-Analysis Framework. We systematically searched multiple databases from inception till February 2021 and included peer-reviewed articles conducted with/for older adults residing in SSA. Conventional content analysis was employed to categorize studies into subject-related areas.

RESULTS

We included 512 studies (quantitative = 426, qualitative = 71 and mixed-method = 15). Studies were conducted in 32 countries. Quantitative studies included were observational studies: cross-sectional (n = 250, 59%), longitudinal (n = 126, 30%), and case-control (n = 12, 3%); and experimental studies: pre-post design (n = 4, 1%), randomized control trial (RCT, n = 12, 3%); and not reported (n = 21, 5%). Fifteen qualitative studies did not state their study design; where stated, study design ranged from descriptive (n = 14, 20%), ethnography (n = 12, 17%), grounded theory (n = 7, 10%), narrative (n = 5, 7%), phenomenology (n = 10, 14%), interpretative exploratory (n = 4, 6%), case studies (n = 4, 6%). Of the 15 mixed-method studies, seven did not state their mixed-method design. Where stated, design includes concurrent (n = 1), convergent (n = 1), cross-sectional (n = 3), informative (n = 1), sequential exploratory (n = 1) and retrospective (n = 2). Studies were classified into 30 (for quantitative studies) and seven (for qualitative and mixed-method) subject-related areas. HIV/AIDs-related and non-communicable diseases-related studies were the most predominant subject-related areas. No studies explored the transdisciplinary co-production of interventions.

CONCLUSIONS

There are glaring gaps in ageing research in SSA, especially mixed-methods and RCTs. A large number of studies focused on HIV/AIDs and non-communicable disease-related studies. National and international funding agencies should set up priority funding competitions for transdisciplinary collaborations in ageing research.

A Systematic Review of Studies Reporting Antibiotic Pharmacokinetic Data in the Cerebrospinal Fluid of Critically Ill Patients with Uninflamed Meninges

Ventriculostomy-associated infections in critically ill patients remain therapeutically challenging because of drug- and disease-related factors that contribute to suboptimal antibiotic concentrations in cerebrospinal fluid. Optimal antibiotic dosing for the treatment and prevention of such infections should be based on robust and contextually specific pharmacokinetic data. The objects of this study were to describe and critically appraise studies with reported antibiotic concentrations or pharmacokinetic data in cerebrospinal fluid of critically ill patients without meningeal inflammation. We systematically reviewed the literature to identify published reports and studies describing antibiotic concentrations, pharmacokinetics, and pharmacokinetics/pharmacodynamics in cerebrospinal fluid of critically ill patients with uninflamed meninges. Fifty-eight articles met the inclusion criteria. There was significant heterogeneity in methodologies and results. When available, antibiotic pharmacokinetic parameters displayed large intersubject variability. Intraventricular dosing achieved substantially higher antibiotic concentrations in cerebrospinal fluid than did intravenous doses. Few studies conducted a robust pharmacokinetic analysis and described relevant clinical pharmacokinetic/pharmacodynamic indices and exposure targets in cerebrospinal fluid. Robust and clinically relevant antibiotic pharmacokinetic data describing antibiotic disposition in cerebrospinal fluid are necessary. Such studies should use a standardized approach to accurately describe pharmacokinetic variability. These data should ideally be tied to clinical outcomes whereby therapeutic targets in the cerebrospinal fluid can be better defined. Altered dosing strategies, in conjunction with exploring the utility of therapeutic drug monitoring, can then be developed to optimize antibiotic exposure with the goal of improving outcomes in this difficult-to-treat patient group.

Use of Intraventricular Medications in Critically Ill Patients: A Systematic Review

New evidence and increased use of intracranial devices have increased the frequency of intraventricular (IVT) medication administration in the neurologic intensive care unit. Significant benefits and risks are associated with administration of medications directly into the central nervous system. This review summarizes important literature, along with key information for clinicians regarding the administration, dosing, monitoring, and adverse effects related to IVT medication usage. Multiple medications have supporting literature for their use in critically ill patients including amphotericin B, aminoglycosides, colistimethate, daptomycin, quinupristin/dalfopristin, vancomycin, alteplase, and nicardipine. Sterile preparation and delivery, along with different types of devices that support medication administration, are also reviewed. One randomized, placebo-controlled trial of alteplase demonstrated decreased mortality but no change in good functional outcome. Other reports of IVT medication use are mainly limited to case reports and retrospective case series. There is a need for increased research on the topic; however, several practical barriers decrease the likelihood of a large, placebo-controlled, prospective study for most indications. Providers should consider implementing protocols to maximize safety of IVT medication delivery to ensure optimal patient outcomes.

Global prevalence and distribution of vancomycin resistant, vancomycin intermediate and heterogeneously vancomycin intermediate Staphylococcus aureus clinical isolates: a systematic review and meta-analysis

Vancomycin-resistant Staphylococcus aureus (VRSA), Vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA) are subject to vancomycin treatment failure. The aim of the present study was to determine their precise prevalence and investigate prevalence variability depending on different years and locations. Several international databases including Medline (PubMed), Embase and Web of Sciences were searched (data from 1997 to 2019) to identify studies that addressed the prevalence of VRSA, VISA and hVISA among human clinical isolates around the world. Subgroup analyses and meta-regression were conducted to indicate potential source of variation. Publication bias was assessed using Egger's test. Statistical analyses were conducted using STATA software (version 14.0). Data analysis showed that VRSA, VISA and hVISA isolates were reported in 23, 50 and 82 studies, with an overall prevalence of 1.5% among 5855 S. aureus isolates, 1.7% among 22,277 strains and 4.6% among 47,721 strains, respectively. The overall prevalence of VRSA, VISA, and hVISA before 2010 was 1.2%, 1.2%, and 4%, respectively, while their prevalence after this year has reached 2.4%, 4.3%, and 5.3%. The results of this study showed that the frequency of VRSA, VISA and hVISA after 2010 represent a 2.0, 3.6 and 1.3-fold increase over prior years. In a subgroup analysis of different strain origins, the highest frequency of VRSA (3.6%) and hVISA (5.2%) was encountered in the USA while VISA (2.1%) was more prevalent in Asia. Meta-regression analysis showed significant increasing of VISA prevalence in recent years (p value ≤ 0.05). Based on the results of case reports (which were not included in the calculations mentioned above), the numbers of VRSA, VISA and hVISA isolates were 12, 24 and 14, respectively, among different continents. Since the prevalence of VRSA, VISA and hVISA has been increasing in recent years (especially in the Asian and American continents), rigorous monitoring of vancomycin treatment, it's the therapeutic response and the definition of appropriate control guidelines depending on geographical regions is highly recommended and essential to prevent the further spread of vancomycin-resistant S. aureus.

The current role of glycopeptides in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in not neutropenic adults: the viewpoint of a group of Italian experts

Staphylococcus aureus is still an important problem in clinical and therapeutic area, worldwide. In Italy, in recent years, methicillin resistance remained stable, yet considerably high, the percentage of strains of MRSA being around 40%. It was deemed interesting and timely to carry out a consensus conference using the RAND/UCLA method to collect the opinion of a group of experts in infectious diseases on the role of glycopeptides in the management of MRSA infections within several clinical scenarios and namely in pneumonia, bacteremia and endocarditis, joint replacement infections, skin and soft tissue infections, diabetic foot, abdominal infections and central nervous system infections. The scenarios proposed by the Scientific Committee have been validated by a group of experts in infectious diseases and then voted in three meetings of infectious disease specialists. The results obtained on each individual condition were analyzed and therapeutic recommendations on each of these were released.

Linezolid for the Treatment of Patients with Central Nervous System Infection

Objective:

To review the available evidence regarding the use of linezolid for the treatment of patients with central nervous system (CNS) infections.

Data Sources:

Relevant studies were identified through searches of the PubMed, Current Contents, and Cochrane databases (publications archived until October 2006).

Study Selection and Data Extraction:

Case reports, case series, prospective and retrospective studies, and randomized controlled trials were eligible for inclusion in our review if they evaluated the effectiveness and safety of linezolid for the treatment of patients with CNS infections.

Data Synthesis:

In 18 (42.9%) of the 42 relevant cases identified, patients had undergone neurosurgical operations and/or had prosthetic devices. Meningitis was the most common CNS infection, accounting for 20 (47.6%) cases. Other CNS infections included brain abscesses (14; 33.3%), ventriculitis (5; 11.9%), and ventriculo-peritoneal shunt infection (3; 7.1%). In the 39 patients in whom the responsible pathogen was isolated, those predominantly responsible for the CNS infections were: penicillin–nonsusceptible Streptococcus pneumoniae (7; 17.9%), vancomycin-resistant enterococci (6; 15.4%), Nocardia spp. (5; 12.8%), methicillin-resistant Staphylococcus epidermidis (4; 10.3%), and methicillin-resistant Staphylococcus aureus (3; 7.7%). Of the 42 patients who received linezolid for the treatment of CNS infections, 38 (90.5%) were either cured or showed clinical improvement of the infection. The mean duration of follow-up was 7.2 months; no recurrent CNS infection was reported.

Conclusions:

The limited published data suggest that linezolid may be considered for the treatment of patients with CNS infections in cases of failure of previously administered treatment or limited available options.

Systematic review of efficacy, pharmacokinetics, and administration of intraventricular vancomycin in adults

Central nervous system infections requiring treatment with intraventricular (IVT) vancomycin are becoming increasingly common with advent of intracranial devices and increasing prevalence of multi-drug resistant and nosocomial organisms. Administering vancomycin via IVT route bypasses the blood-brain barrier to allow localized and controlled delivery directly to the desired site of action, achieving high concentrations for more reliable bactericidal action. This article systematically reviews current literature on IVT vancomycin in adults, compiles current knowledge, and integrates available evidence to serve as a practical reference.Medline (1946-July 2012), Embase (1974-July 2012), and International Pharmaceutical Abstracts (1970-July 2012) were searched using terms vancomycin, intraventricular, shunt infection, cerebrospinal fluid, and intraventriculitis. Seventeen articles were included in this review. Indications for IVT vancomycin included meningitis unresponsive to intravenous antibiotics, ventriculitis, and intracranial device infections. No serious adverse effects following IVT vancomycin have been reported. Dosages reported in literature ranged from 0.075-50 mg/day, with the most evidence for dosages of 5 to 20 mg/day. Duration of therapy most commonly ranged from 7 to 21 days. Therapeutic drug monitoring was reported in 11 studies, with CSF vancomycin levels varying widely from 1.1 to 812.6 mg/L, without clear relationships between CSF levels and efficacy or toxicity. Using IVT vancomycin to treat meningitis, ventriculitis, and CNS device-associated infections appears safe and effective based on current evidence. Optimal regimens are still unclear, and dosing of IVT vancomycin requires intricate consideration of patient specific factors and their impact on CNS pathophysiology. Higher-quality clinical trials are necessary to characterize the disposition of vancomycin within CNS, and to determine models for various pathophysiological conditions to facilitate better understanding of effects on pharmacokinetic and pharmacodynamic parameters.

Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

New therapeutic choices for infections caused by methicillin-resistant Staphylococcus aureus

In recent years, a marked increase in the incidence of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has occurred in many countries. This review addresses the effectiveness and limitations of drugs classically used for the treatment of MRSA, e.g. vancomycin, and also newer anti-MRSA antimicrobials, e.g. second-generation glycolipopeptides, tigecycline, and beta-lactams.

Community-acquired methicillin-resistant Staphylococcus aureus meningitis complicated by cerebral infarction. Role of antibiotic combination of linezolid plus levofloxacin

The therapeutic options available for central nervous system (CNS) infections due to resistant Gram-positive cocci remain limited. We report an unusual case of community-acquired methicillin-resistant Staphylococcus aureus meningitis complicated by cerebral infarction in the middle cerebral artery territory in a previously healthy young male. After an initial vancomycin-based regimen, treatment was completed with a seven-week course of linezolid and levofloxacin. The potential role of such a combination and, particularly, linezolid as a first-line therapy in serious CNS infections is also discussed.

[Presumptive bacterial meningitis in adults: initial antimicrobial therapy]

CSF sterilization should be obtained very rapidly to reduce both mortality and morbidity due to bacterial meningitis. Thus, antibiotic treatment should be adapted to the suspected bacterium and administered as early as possible at high dosage with - if necessary - a loading dose and continuous perfusion. The rates of abnormal susceptibility to penicillin of Streptococcus pneumoniae, Neisseria meningitis and Haemophilus influenzae are 37%, 30% and 12% respectively. Thus, ceftriaxone or cefotaxim must be used as empirical treatment. Listeria monocytogenes remains fully susceptible to aminopenicillin, so, the combination aminopenicillin and aminoglycoside is the first-line treatment. Antibiotic resistance, allergy or contra-indications, are in fact rare but in these cases, antibiotic combinations are often needed. The latter are more or less complex and clinically validated; they include molecules such as vancomycine, fosfomycin, fluoroquinolone or linezolid.

Linezolid for the treatment of drug-resistant infections

Multidrug-resistant pathogens have become increasingly common in contemporary healthcare. Specific to Gram-positive pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is of particular concern, as it has been associated with increased hospital length of stay, higher healthcare expenditures and poorer outcomes. To date, linezolid is the first and only oxazolidinone approved by the US FDA for the treatment of infections caused by Gram-positive pathogens, including MRSA. This article will serve as a comprehensive review of linezolid, including an overview of the current market and its in vitro activity, with an in-depth review of its pharmacokinetic and pharmacodynamic profile. Emphasis will be placed on clinical data for the drug, both on- and off-label. The article will conclude with a brief overview of linezolid's pharmacoeconomic implications and safety profile, followed by a commentary and 5-year prospective analysis remarking on the future of the antimicrobial field as it relates to MRSA.

Successful treatment of meningoencephalitis caused by methicillin-resistant Staphylococcus aureus with intravenous linezolid in an allogeneic cord blood stem cell transplant recipient

Methicillin-resistant Staphylococcus aureus (MRSA) is an infectious pathogen that commonly occurs after stem cell transplantation. We report a case of meningoencephalitis with multiple abscess formation caused by MRSA, which occurred in a 62-y-old female soon after allogeneic cord blood transplantation, and which was successfully treated by the administration of intravenous linezolid.

Pharmacologic options for CNS infections caused by resistant Gram-positive organisms

Infectious disease continues to evolve, presenting new and challenging clinical situations for practitioners. Specific to device-related and neurosurgical-related CNS infections, Gram-positive organisms are of growing concern. Current Infection Disease Society of America guidelines for the treatment of CNS infections offer little direction after conventional therapy, consisting of vancomycin, has failed or the patient has demonstrated intolerance. A review of literature evaluating alternative therapies, specifically linezolid, quinupristin/dalfopristin, daptomycin and tigecycline, will be presented. Interpretations of these data are offered followed by a brief presentation of future therapies, including ortavancin, telavancin, dalbavancin, ceftobiprole and iclaprim, all of which possess potent Gram-positive activity.

Treatment of Meningitis Caused by Methicillin-Resistant Staphylococcus aureus with Linezolid

Methicillin-resistant Staphylococcus aureus (MRSA) is increasing in prevalence both in nosocomial and in community settings. Treatment of such infections, particularly in the central nervous system (CNS), is problematic, as available options are limited. Linezolid is a new antibiotic with activity against Gram-positive cocci, including MRSA, and has good penetration into the cerebrospinal fluid. To our knowledge, there are only three case reports of successful treatment of CNS infections caused by MRSA with linezolid; we report herein a fourth such case. Clinical trials to address the role of linezolid in CNS infections are urgently needed.

Antibiotic resistance in Staphylococcus aureus and its relevance in therapy

Staphylococcus aureus is a major cause of infections. Only approximately 20% of the strains remain sensitive to penicillin. Beta-lactamase stable penicillins such as flucloxacillin form the mainstay of treatment of staphylococcal infection. Meticillin-resistant S. aureus (MRSA) are resistant to all beta-lactam antibiotics. Glycopeptide antibiotics are effective against most MRSA strains but, in the last few years, isolates of MRSA that have reduced susceptibility to glycopeptides (glycopeptide-intermediate S. aureus) have been isolated. Some strains exhibit frank resistance to glycopeptides (vancomycin-resistant S. aureus). Infections due to these strains are difficult to treat. This review summarises the therapeutic options for MRSA, glycopeptide-intermediate S. aureus and vancomycin-resistant S. aureus. Novel therapeutic strategies such as immunotherapy and vaccines are also discussed.

Linezolid cerebrospinal fluid concentration in central nervous system infection

We report two cases of central nervous system infection due to methicillin-resistant Staphylococcus epidermidis treated with linezolid. The first case was a 72-year old woman with ventriculitis in the presence of intraventricular catheter: therapeutic effectiveness was documented clinically and microbiologically; serum and cerebrospinal fluid levels were measured after the first and fourth doses: trough linezolid concentrations in cerebrospinal fluid were 1.44 and 2.9 mg/L respectively, higher than the minimum inhibitory concentration (MIC). The second case was a 27-year old man with post-traumatic cerebral abscess; during 5 days linezolid was not found in his cerebrospinal fluid despite very high serum level peak, and the drug was not detectable in cerebral tissue surgically removed after 14 days of therapy. Linezolid may not reach therapeutic concentrations in cerebrospinal fluid, and, when possible, we suggest that drug levels be monitored.

Antimicrobial susceptibility patterns and characterization of clinical isolates of Staphylococcus aureus in KwaZulu-Natal province, South Africa

Background

Antimicrobial resistance of Staphylococcus aureus especially methicillin-resistant S. aureus (MRSA) continues to be a problem for clinicians worldwide. However, few data on the antibiotic susceptibility patterns of S. aureus isolates in South Africa have been reported and the prevalence of MRSA in the KwaZulu-Natal (KZN) province is unknown. In addition, information on the characterization of S. aureus in this province is unavailable. This study investigated the susceptibility pattern of 227 S. aureus isolates from the KZN province, South Africa. In addition, characterization of methicillin-sensitive S. aureus (MSSA) and MRSA are reported in this survey.

Methods

The in-vitro activities of 20 antibiotics against 227 consecutive non-duplicate S. aureus isolates from clinical samples in KZN province, South Africa were determined by the disk-diffusion technique. Isolates resistant to oxacillin and mupirocin were confirmed by PCR detection of the mecA and mup genes respectively. PCR-RFLP of the coagulase gene was employed in the characterization of MSSA and MRSA.

Results

All the isolates were susceptible to vancomycin, teicoplanin and fusidic acid, and 26.9% of isolates studied were confirmed as MRSA. More than 80% of MRSA were resistant to at least four classes of antibiotics and isolates grouped in antibiotype 8 appears to be widespread in the province. The MSSA were also susceptible to streptomycin, neomycin and minocycline, while less than 1% was resistant to chloramphenicol, ciprofloxacin, rifampicin and mupirocin. The inducible MLS_B phenotype was detected in 10.8% of MSSA and 82% of MRSA respectively, and one MSSA and one MRSA exhibited high-level resistance to mupirocin. There was good correlation between antibiotyping and PCR-RFLP of the coagulase gene in the characterization of MRSA in antibiotypes 1, 5 and 12.

Conclusion

In view of the high resistance rates of MRSA to gentamicin, erythromycin, clindamycin, rifampicin and trimethoprim, treatment of MRSA infections in this province with these antibacterial agents would be unreliable. There is an emerging trend of mupirocin resistance among S. aureus isolates in the province. PCR-RFLP of the coagulase gene was able to distinguish MSSA from MRSA and offers an attractive option to be considered in the rapid epidemiological analysis of S. aureus in South Africa. Continuous surveillance on resistance patterns and characterization of S. aureus in understanding new and emerging trends in South Africa is of utmost importance.