Prolonged use of linezolid in bone and joint infections: a retrospective analysis of adverse effects.

OBJECTIVES: Antibiotic treatment for bone and joint infections generally lasts for 6 weeks or longer. Linezolid may be a good option for treating bone and joint infections, but there is an increased risk of potential serious adverse drug events (ADEs) when used for more than 28 days. The aim of this study was to obtain detailed information on the type and time to occurrence of the patient-reported ADEs, the dynamics of haematopoiesis over time, and the reasons for early discontinuation of linezolid when used for an intended maximum duration of 12 weeks. METHODS: This single-centre retrospective study was conducted at the Sint Maartenskliniek in The Netherlands. Patients were included if they were planned to use linezolid for more than 28 days. The main reason for discontinuation of linezolid, the ADE according to the Naranjo score, and the time to occurrence of ADEs were analysed. RESULTS: Among 78 patients, drug toxicity led to early discontinuation of linezolid in 11 (14%) patients before and nine (12%) after 28 days of therapy. The median treatment duration was 42 days. Gastrointestinal intolerance (42%) and malaise (32%) were the most common ADEs. In 75% of the cases the ADE occurred within 28 days of therapy. Sixty-seven patients were able to continue linezolid beyond 28 days, 87% of whom completed therapy as scheduled. Severe cytopenia, according to the Common Terminology Criteria for Adverse events (CTCA), was observed in four patients and was reversible after discontinuation of linezolid. One patient suffered optic neuropathy related to linezolid use. CONCLUSIONS: Linezolid could be considered an alternative option to the current standard of IV glycopeptides for the treatment of bone and joint infection for up to 12 weeks. If patients pass the first 28 days of therapy, the likelihood of successful completion of therapy is high with a low risk of serious ADEs.

How to use quality indicators for antimicrobial stewardship in your hospital: a practical example on outpatient parenteral antimicrobial therapy.

BACKGROUND: Antimicrobial stewardship (AMS) teams are responsible for performing an AMS programme in their hospitals that aims to improve the quality of antibiotic use. Measuring the quality of antimicrobial use is a core task of a stewardship team. Measurement provides insight into the current quality of antibiotic use and allows for the establishment of goals for improvement. Yet, a practical description of how such a quality measurement using quality indicators (QIs) should be performed is lacking. OBJECTIVES: To provide practical guidance on how a stewardship team can use QIs to measure the quality of antibiotic use in their hospital and identify targets for improvement. SOURCES: General principles from implementation science, peer-reviewed publications, and experience from clinicians and researchers with AMS experience. CONTENT: We provide step-by-step guidance on how AMS teams can use QIs to measure the quality of antibiotic use. The principles behind each step are explained and illustrated with the description and results of an audit of patients receiving outpatient parenteral antimicrobial therapy in four Dutch hospitals. IMPLICATIONS: Improving the quality of antibiotic use is impossible without first gaining insight into that quality by performing a measurement with validated QIs. This step-by-step practice example of how to use quality indicators in a hospital will help AMS teams to identify targets for improvement. This enables them to perform their AMS programme more effectively and efficiently.

Debridement, antibiotics, and implant retention after revision arthroplasty : antibiotic mismatch, timing, and repeated DAIR associated with poor outcome.

AIMS: Debridement, antibiotics, and implant retention (DAIR) is a widely accepted form of surgical treatment for patients with an early periprosthetic joint infection (PJI) after primary arthroplasty. The outcome of DAIR after revision arthroplasty, however, has not been reported. The aim of this study was to report the success rate of DAIR after revision arthroplasty with a follow-up of two years. METHODS: This retrospective study, conducted at the Sint Maartenskliniek, Nijmegen, the Netherlands, included 88 patients who underwent DAIR within 90 days of revision total hip or total knee arthroplasty between 2012 and 2019. Details of the surgical procedures and PJI were collected. Univariate analysis and a subgroup analysis of the culture-positive group were performed. Kaplan-Meier survivorship curves were constructed. RESULTS: The overall success rate of DAIR, with respect to the retention of components and the cure of infection, was 68% after two years. DAIR performed with an interval of > 30 days after the index revision procedure (odds ratio (OR) 0.24 (95% confidence interval (CI) 0.08 to 0.72); p = 0.008), a repeated DAIR within 90 days (OR 0.37 (95% CI 0.14 to 0.97); p = 0.040), and the use of an immunosuppressive agent (OR 0.13 (95% CI 0.02 to 0.67); p = 0.012) were associated with a significantly reduced success rate. In the culture-positive group, a mismatch between the antibiotic treatment and the susceptibility of the organism was associated with a significantly lower success rate (OR 0.13 (95% CI 0.03 to 0.62); p = 0.007). CONCLUSION: DAIR is an acceptable form of surgical treatment for patients with a suspected early PJI after revision arthroplasty of the hip or knee. DAIRs performed after a prolonged interval, multiple DAIRs, and antibiotic mismatches were significantly associated with an increased risk of failure. Optimization of the host immune response and the prevention of antibiotic mismatch are modifiable factors that may improve the outcome. The high rate of mismatches was an important finding, underlining the need for a review of the local microbiological data, which might improve the outcome. Cite this article: Bone Joint J 2022;104-B(4):464-471.

Better diagnostic value of tissue cultures obtained during mini-open and arthroscopic procedures compared with sterile punctures to identify periprosthetic shoulder infections: a retrospective cohort study.

BACKGROUND: This study aimed to determine the sensitivity and specificity of sterile shoulder needle aspiration and cultures obtained during arthroscopic and mini-open procedures for detecting periprosthetic shoulder infections using tissue cultures from revision surgery as the gold standard. METHODS: All shoulder arthroplasty patients who underwent a synovial fluid puncture between August 2012 and February 2018 were selected. In addition, arthroplasty patients with cultures obtained during arthroscopic or mini-open procedures between May 2014 and May 2021 were selected. When sterile punctures or biopsy procedures were followed by revision surgery with collection of 6 tissue cultures, patients were included in the study and efficacy measures were calculated. RESULTS: Fifty-six patients were included in this study (with 57 punctures) and underwent analysis of puncture results after exclusions. Positive puncture results were found for Cutibacterium acnes, Staphylococcus aureus, Staphylococcus hominis, Actinomyces neuii, and Proteus mirabilis. These puncture cultures showed a sensitivity of 20.0% and specificity of 90.6%. From May 2014 to May 2021, 51 biopsy procedures were performed (15 arthroscopic and 36 mini-open); 37 biopsy procedures were included in this study (12 arthroscopic and 25 mini-open) for analysis after exclusions. Positive culture results were found for C acnes, Staphylococcus epidermidis, Staphylococcus saccharolyticus, and Streptococcus species. Arthroscopic biopsy cultures showed a sensitivity of 60.0% and specificity of 85.7%. For the mini-open biopsy cultures, the sensitivity and specificity were 66.7% and 85.7%, respectively. CONCLUSIONS: Sterile punctures for culture have a low sensitivity and a high specificity for diagnosing periprosthetic shoulder infections. Tissue cultures obtained during mini-open and arthroscopic procedures have a higher sensitivity for detecting periprosthetic shoulder infections.

Cell-mediated immune responses to inactivated trivalent influenza-vaccination are decreased in patients with common variable immunodeficiency.

Influenza-specific cell-mediated immune (CMI) responses can protect from influenza, but may be decreased in CVID-patients since defects in CMI responses have been demonstrated in CVID-patients. Therefore CMI responses were evaluated in 15 CVID-patients and 15 matched healthy controls (HC) by determining frequencies of interferon (IFN)γ-producing PBMC, and frequencies of IFNγ-, interleukin (IL)-2- and tumour necrosis factor (TNF)α-producing CD4+ and CD8+ T-cells before and after influenza vaccination using IFNγ enzyme-linked immunospot (IFNγ-ELISpot) and flow cytometry. Humoral responses were determined using haemagglutination inhibition assay. In CVID-patients the number of spotforming PBMC in the IFNγ-ELISpot did not increase following influenza vaccination, in contrast to HC. In flow cytometry, the frequencies of IFNγ-producing T-cells decreased in CVID-patients after influenza vaccination, while in HC the frequencies of IFNγ-production flow cytometry increased. Concluding, CMI responses following influenza vaccination are hampered in CVID-patients compared to HC. Additional protective strategies against influenza other than vaccination are warranted.

Patients with humoral primary immunodeficiency do not develop protective anti-influenza antibody titers after vaccination with trivalent subunit influenza vaccine.

Yearly influenza vaccination is recommended for patients with humoral primary immunodeficiency (hPID). However, humoral responses following vaccination can be expected to be reduced in these patients. The efficacy of influenza vaccination in patients with hPID, anti-influenza antibody responses was assessed in 26 patients with hPID and 26 matched healthy controls (HC) using hemagglutination inhibition assay. Following vaccination, geometric mean titers (GMT) significantly increased for all influenza strains in the HC group, but only for A/H1N1 in the patient group. Fold increase in anti-influenza titer and seroprotection rates were lower for patients than for HC for A/H3N2 and A/H1N1, leading to postvaccination titer > or =40 in only 29% and 83% vs. 77% and 100%, respectively. Previous vaccination in patients and treatment with IVIg did not result in a higher rate of postvaccination titer > or =40. In conclusion, patients with hPID show hardly any humoral response following influenza vaccination.

Glutamate-rich protein (GLURP) induces antibodies that inhibit in vitro growth of Plasmodium falciparum in a phase 1 malaria vaccine trial.

The glutamate-rich protein (GLURP) of P. falciparum is the target of cytophilic antibodies which are significantly associated with protection against clinical malaria. A phase 1 clinical trial was conducted in healthy adult volunteers with the long synthetic peptide (LSP) GLURP(85-213) combined with either Aluminum Hydroxide (Alum, 18 volunteers) or Montanide ISA 720 (ISA, 18 volunteers) as adjuvants. Immunizations with 10, 30 or 100 microg GLURP(85-213) were administered subcutaneously at days 0, 30, and 120. Adverse events occurred more frequently with increasing dosage of GLURP(85-213) LSP and were more prevalent in the ISA group. Serious vaccine-related adverse events were not observed. The vaccine induced dose-dependent cellular and humoral immune responses, with high levels of (mainly cytophilic IgG1) antibodies that recognize parasites by immunofluorescence (IFA). Plasma samples collected 30 days after the last immunization induced a dose-dependent inhibition of parasite growth in vitro in the presence of monocytes. In conclusion, immunizations with GLURP(85-213) LSP formulations induce adverse events but can be administered safely, generating antibodies with capacity to mediate growth-inhibitory activity against P. falciparum in vitro.

Serious psychiatric symptoms after chloroquine treatment following experimental malaria infection.

OBJECTIVE: To report serious psychiatric symptoms after standard chloroquine treatment following human malaria infection induced for research. CASE SUMMARY: A 34-year-old healthy woman volunteered to participate in a study of malaria treatment. She was infected on day 0 with a chloroquine-susceptible strain of Plasmodium falciparum and was treated with a standard 3-day course of chloroquine from day 9 onward, following a positive blood smear (parasitemia 0.001%). On day 10, the blood smear became negative. On day 11, she developed a psychotic disorder not otherwise specified, most probably caused by chloroquine use, with symptoms of depersonalization and anxiety. The diagnosis of delirium was considered but ruled out because of clear consciousness with lack of diurnal fluctuations. She refused to take antipsychotic medication. Three weeks later, the woman still encountered serious concentration problems. All complaints gradually subsided over the next 4 months, after which she felt completely recovered. Plasma chloroquine concentrations were within the therapeutic range. DISCUSSION: Chloroquine may achieve high concentrations in the brain and has a long half-life. As quinolines, the antimalarials may have the same pathologic activity as the fluoroquinolone antibiotics in acting as N-methyl-d-aspartate agonists and gamma-aminobutyric acid antagonists. Application of the Naranjo probability scale indicated that, in this patient, chloroquine was the probable cause of the serious psychiatric symptoms. CONCLUSIONS: Our unique observation demonstrates that serious psychiatric symptoms can emerge as a rare occurrence during standard chloroquine therapy. This adverse effect may persist for several months.

Testing vaccines in human experimental malaria: statistical analysis of parasitemia measured by a quantitative real-time polymerase chain reaction.

Clinical trials are an essential step in evaluation of safety and efficacy of malaria vaccines, and human experimental malaria infections have been used for evaluation of protective immunity of Plasmodium falciparum malaria. In this study, a quantitative real-time polymerase chain reaction was used to measure P. falciparum malaria parasitemia in non-immune volunteers who had been experimentally infected by mosquito bites. Based on a remarkably small variation in the kinetics of parasitemia, a statistical model was developed that provides detailed estimates of pre-patent periods and parasite multiplication of blood stages. Using this model, we could predict results on vaccine efficacy for 1) pre-erythrocytic vaccines in the asymptomatic incubation period and 2) asexual stage vaccines after a limited number of multiplication cycles. The model shows that stage-specific vaccines even with limited efficacy can be highly efficacious when used in combination. This P. falciparum challenge method significantly adds to the potential to evaluate efficacy of candidate malaria vaccines before going into field trials.

Quantification of Plasmodium falciparum gametocytes in differential stages of development by quantitative nucleic acid sequence-based amplification.

Two quantitative nucleic acid sequence-based amplification assays (QT-NASBA) based on Pfs16 and Pfs25, have been developed to quantify sexual stage commitment and mature gametocytes of Plasmodium falciparum. Pfs16 mRNA is expressed in all sexual forms including sexually committed ring stages while expression of Pfs25 mRNA is restricted to late stage gametocytes. Both assays showed a sensitivity of one sexual stage parasite/microl of blood. Blood samples from experimentally infected non-immune human volunteers were tested for Plasmodium falciparum by standard microscopy, a previously developed asexual 18S rRNA QT-NASBA, Pfs16 and Pfs25 mRNA QT-NASBA. Pfs16 QT-NASBA was positive in 9 out of 10 volunteers within 48 h after first detection of 18S rRNA, mostly before or at the day of positive microscopy. In contrast, the Pfs25 mRNA QT-NASBA was negative during the 28 days of follow-up, but consistently positive in gametocyte samples from naturally infected Kenyan patients. These data suggest that sexual stage commitment can occur early in the blood-stage infection without successful maturation into infectious gametocytes. In conclusion, Pfs16 and Pfs25 QT-NASBA assays in combination with a previously developed asexual stage QT-NASBA allow for the separate quantification of all developmental stages present in the circulation. The application of sexual stage QT-NASBA assays may contribute to a better understanding of the biology and epidemiology of malaria transmission.

Persistent leukocyturia and loss of renal function in a prospectively monitored cohort of HIV-infected patients treated with indinavir.

Symptomatic nephrotoxicity is a well-known complication of indinavir treatment. However, little is known about the relevance of other abnormalities, such as leukocyturia during use of indinavir. We determined the prevalence, risk factors, and consequences of persistent leukocyturia in a prospectively monitored cohort of indinavir users in three adult outpatient clinics. Patients were monitored for nephrotoxicity at regular visits (every 3 months) between August 1998 and September 2000. Monitoring involved urine dipstick analysis and microscopy for pH, erythrocytes, leukocytes, and indinavir crystals. The urine albumin concentration/creatinine concentration ratio and serum creatinine and indinavir plasma concentrations were measured, and urinary tract infection was excluded. Urologic symptoms were retrieved from medical records. Of 184 patients with at least one assessment, 35% had leukocyturia (i.e., >75 cells/microL) at least once during the study period, which coincided with mild increase in the serum albumin level, erythrocyturia, and crystalluria. Thirty-two (24%) of 134 patients with two or more assessments had persistent leukocyturia (i.e., on two or more occasions). Risk factors were indinavir plasma concentration of >9 mg/L, urine pH of >5.7, and crystalluria. Persistent leukocyturia was associated with a gradual loss of renal function but not with urologic symptoms. The data show that leukocyturia is a frequent finding and emphasize the need for monitoring renal function during indinavir treatment, even in the absence of urologic symptoms.

The influence of efavirenz on the pharmacokinetics of a twice-daily combination of indinavir and low-dose ritonavir in healthy volunteers.

OBJECTIVE: This study evaluated the effect of multiple-dose efavirenz on the steady-state pharmacokinetics of the combination of indinavir (800 mg) and low-dose ritonavir (100 mg) twice a day, in which ritonavir is used to increase indinavir plasma concentrations. METHODS: Eighteen healthy male volunteers participated in this multiple-dose, 1-arm, 2-period interaction study. They took a combination of 800 mg indinavir and 100 mg ritonavir with food for 15 days. From days 15 to 29, a once-daily administration of 600 mg efavirenz was added to the combination. Pharmacokinetics of indinavir and ritonavir on days 15 and 29 were compared. RESULTS: Fourteen volunteers completed the study. The addition of efavirenz resulted in significant reductions (P <.01) in indinavir area under the curve (AUC, -25%), trough concentration (C(min), -50%), and maximum concentration (C(max), -17%). All indinavir C(min) levels on day 29 remained equivalent to or above the mean C(min) value described for the regimen of 800 mg indinavir three times a day, without ritonavir (0.15 mg/L). Changes in ritonavir AUC, C(min), and C(max) were -36%, -39%, and -34%, respectively. Pharmacokinetics of efavirenz on day 29 were comparable with published data. CONCLUSIONS: The addition of efavirenz to a combination of 800 mg indinavir and 100 mg ritonavir twice daily results in significant decreases in AUC, C(max), and especially C(min) of indinavir. The dose of indinavir or ritonavir should be increased to maintain similar indinavir drug levels after addition of efavirenz to the indinavir-ritonavir combination. Dose modifications may not be needed in antiretroviral-naive human immunodeficiency virus-infected patients if the reference C(min) of the regimen of 800 mg indinavir 3 times a day is considered to be adequate.