Apport des examens biologiques dans le diagnostic positif, la détermination de l’étiologie et le suivi d’une méningite suspectée bactérienne

Heparin Binding Protein in Early Differential Diagnosis of Bacterial Meningitis

Heparin-binding protein is a serine protease that is mobilized rapidly from emigrating polymorphonuclear leukocytes that acts as a chemoattractant activator of monocyte and macrophages. We investigated the potential role and efficacy of serum and cerebrospinal fluid heparin binding protein in differentiating bacterial meningitis from tuberculosis and viral meningitis. A case diagnosed with acute bacterial meningitis (n:37), viral meningitis (n:30) and tuberculous meningitis (n:30) was included in this study. The diagnosis was based on history, clinical criteria, cerebrospinal fluid examination, latex agglutination and culture, and response to therapy. Heparin-binding protein was measured using enzyme-linked immunosorbent technique in both cerebrospinal fluid and serum. Cerebrospinal fluid heparin-binding protein levels were 7.81 ± 0.23 ng/mL in bacterial meningitis, 6.11 ± 0.3 ng/mL in tuberculosis meningitis and 5.75 ± 0.1 ng/mL in viral meningitis. The mean serum level was 14.98 ± 1.1 ng/mL in bacterial meningitis, 6.89 ± 0.4 ng/mL in tuberculosis meningitis, and 6.02 ± 0.4 ng/mL in viral meningitis. Both heparin-binding protein levels were significantly higher in patients with bacterial meningitis. We found that serum and cerebrospinal fluid heparin binding protein is a useful marker for differentiating bacterial meningitis from non-bacterial meningitis.

Role of cerebrospinal fluid lactate in diagnosing meningitis in critically ill patients

BACKGROUND

Meningitis is a life-threatening clinical condition associated with high mortality and morbidity. Early diagnosis and specific treatment may improve outcomes. Lack of specific clinical signs or tests make the diagnosis challenging.

AIM

To assess the efficacy of cerebrospinal fluid (CSF) lactate in diagnosing meningitis in critically ill patients.

METHODS

A prospective, observational cohort study was carried out in a neuro-medical intensive care unit (ICU) over a 22 mo period. Adult patients, with suspected meningitis admitted in ICU, were serially recruited. Patients who refused consent, those with peripheral sensorineural deficit, or with any contraindication to lumber puncture were excluded. CSF cytology, bio-chemistry, lactates, culture and polymerase chain reaction based meningo-encephalitis panel were evaluated. Patients were divided in two groups based on clinical diagnosis of meningitis. The efficacy of CSF lactate in diagnosing meningitis was evaluated and compared with other tests.

RESULTS

Seventy-one patients were included and 23 were diagnosed with meningitis. The mean values of CSF total leucocyte count (TLC), proteins and lactates were significantly higher in meningitis group. There was a significant correlation of CSF lactate levels with CSF cultures and meningo-encephalitis panel. CSF lactate (> 2.72 mmol/L) showed good accuracy in diagnosing meningitis with an area under the curve of 0.81 (95% confidence interval: 0.69-0.93), sensitivity of 82.6%, and specificity 72.9%. These values were comparable to those of CSF TLC and protein. Twelve patients with bacterial meningitis had significantly higher CSF lactate (8.9 ± 4.7 mmol/L) than those with non-bacterial meningitis (4.2 ± 3.8 mmol/L), P = 0.006.

CONCLUSION

CSF lactate may be used to aid in our diagnosis of meningitis in ICU patients. CSF lactate (> 2.72 mmol/L) showed good accuracy, sensitivity, and specificity in diagnosing meningitis and may also help to differentiate between bacterial and non-bacterial meningitis.

Evaluation of human β‑defensins in the cerebrospinal fluid of suspected meningitis

Human β-defensins (HBDs) are an important class of antimicrobial peptides that have immunomodulatory functions; however, the role of HBDs have not been well explored in the pathogenesis of meningitis. A cross-sectional study was performed to explore the levels of HBD1, HBD2, HBD3, and HBD4 in the cerebrospinal fluid (CSF) of 176 suspected meningitis cases. CSF samples were first subjected to PCR analysis using a set of universal primers targeting a portion of the eubacteria 16S rRNA gene. The analysis demonstrated that 66 samples (37.5%) were PCR-positive, whilst 110 samples (62.5%) were PCR-negative. DNA sequence analysis of the PCR-positive products identified two broad categories of bacteria, Gram-negative (68.2%) and Gram-positive (31.8%). A total of 88 PCR-negative CSF samples showed abnormal leukocyte counts, glucose concentrations, and/or protein concentrations, and were considered abnormal (ABN). The remaining 22 CSF samples were considered normal (NOR). HBD1, HBD2, and HBD4 levels did not exhibit significant differences between PCR-positive, ABN, and NOR CSF samples. However, HBD3 levels were significantly higher in the ABN CSF samples than in the NOR CSF samples (P=0.005). HBD3 levels were also elevated in the PCR-positive CSF samples compared with the NOR CSF samples, but the difference was not significant (P=0.151). HBD2, HBD3, and HBD4 were correlated with leukocyte counts, glucose concentration, and protein concentration. In conclusion, HBD3 levels were significantly elevated in the CSF of suspected meningitis cases regardless of the cause of meningitis. The CSF levels of certain HBDs were affected by specific diagnostic laboratory parameters for meningitis, including leukocyte counts, glucose concentration, and protein concentration.

D-Dimer Combined With CRP Can Improve the Differential Value of Bacterial Meningitis and Tuberculous Meningitis

OBJECTIVE

To explore the diagnostic value of the coagulation marker D-dimer and its combination with the traditional marker C-reactive protein (CRP) in distinguishing bacterial meningitis (BM) from tuberculous meningitis (TM).

METHODS

We performed a retrospective study on specimens from 173 patients with meningitis who were hospitalized at the First Affiliated Hospital of Guangxi Medical University, Guangxi, China, from 2012 through 2020. The patient records were divided into the BM group and the TM group, and hematological parameters D-dimer and CRP were evaluated for the 2 groups.

RESULTS

The levels of D-dimer and CRP in the BM group were significantly higher than those levels in the TM group (P ˂.001 for each), and the sensitivity and specificity of the combined detection of the 2 markers was 86.3% to 100%; the area under the receiver operating characteristic (ROC) curve reached 0.983 (95% confidence interval [CI], 0.966-0.999).

CONCLUSION

D-dimer testing has high specificity in distinguishing between BM and TM; CRP testing also has high sensitivity. The combined diagnosis of the 2 biomarkers helps to distinguish TM from BM.

Assessment of the FilmArray® multiplex PCR system and associated meningitis/encephalitis panel in the diagnostic service of a tertiary hospital

Rapid and accurate diagnosis of meningitis/encephalitis (M/E) is essential for successful patient outcomes. The FilmArray® meningitis/encephalitis Panel (MEP) is a multiplexed PCR test for simultaneous, rapid detection of pathogens directly from cerebrospinal fluid (CSF) samples. 94 prospectively collected CSF specimens from patients with clinical suspicion of infective M/E underwent testing for 14 pathogens simultaneously, including Escherichia coli, Haemophilus influenzae, Neisseria meningitidis, and Varicella zoster. MEP demonstrated 95% agreement with current PCR methods, resulting in 16 diagnosed cases of M/E. Typically, the FilmArray® MEP results were delivered within approximately one hour, contrasting with current practices taking up to 5.6 days. Given the significant morbidity and mortality associated with delayed diagnosis of central nervous system infections, the FilmArray® MEP is a useful addition to the diagnostic capabilities of a clinical microbiology department.

Natural history of ventriculostomy-related infection under appropriate treatment and risk factors of poor outcome: a retrospective study

OBJECTIVE

The authors aimed to describe the natural history of ventriculostomy-related infections (VRIs) under appropriate treatment and to assess risk factors for poor outcome.

METHODS

All patients older than 18 years in whom an external ventricular drain (EVD) had been implanted and who had developed a VRI requiring treatment were included in this retrospective study. D0 was defined as the first day of antibiotic administration. Clinical and biological parameters were compared each day beginning with D1 and ending with D10 to those of D0. The authors defined D0 in a control group as the day a CSF culture came back positive, without any sign of infection. The authors then searched for poor prognostic factors in the VRI group.

RESULTS

Among 567 patients requiring an EVD between January 2007 and October 2017, 39 developed a VRI. Most were monomicrobial infections, and 47 microbes were responsible (45% were gram-positive cocci). Clinical parameters differed significantly from the control group during the first 2 days and then returned to baseline. The CSF parameters differed significantly from the control group for a longer period, returning to baseline after 5 days. CSF sterilization occurred in a median time of 2 days. An intrathecal route or EVD exchange was not associated with a poor outcome. No clinical or biological parameter between D3 and D5 was linked to outcome.

CONCLUSIONS

Clinical status improved faster than CSF parameters (before and after D5, respectively). Some CSF parameters remained abnormal until D10. Body temperature and microbiological cultures normalized faster than other parameters.

C - reactive protein of cerebrospinal fluid, as a sensitive approach for diagnosis of neonatal meningitis

BACKGROUND

Meningitis, is a potentially life-threatening condition that can rapidly progress to permanent brain damage, neurologic problems, and even death. Bacteria and viruses cause the great majority of meningitis disease in infants and children. CRP is used mainly as a marker of inflammation.

OBJECTIVE

This study was conducted to assess the diagnostic value of CSF-CRP levels for differentiating between septic (bacterial) and aseptic infantile meningitis.

METHODS

49 hospitalized infants aged less than two months with suspected meningitis were enrolled in a cross-sectional analytic study. All of patients underwent lumbar puncture to obtain CSF. smears, cultures, cytological and biochemical analysis and latex agglutination testing were carried out on all CSF samples. Latex agglutination test was carried out on all CSF samples using a commercially available kit. CSF-CRP level of all infants was measured using the immunoturbidometric technique.

RESULTS

Of 49 infants in this study, 20 and 29 cases were diagnosed as septic and aseptic meningitis, respectively. The CRP levels were obtained as 0.95±0.68 mg/L in septic and 0.16±0.36 mg/L in aseptic meningitis groups and this difference was statistically significant (p<0.001) between the two groups (0.79±0.32 mg/L). Based on the ROC curve, cut off levels for CRP was obtained 0.17 mg/L. At this level, there was 95% sensitivity and 86% specificity to differentiate septic and aseptic meningitis.

CONCLUSION

CSF-CRP has suitable diagnostic value in distinguishing between infantile bacterial from aseptic meningitis especially in cases of negative bacterial culture of the blood and spinal fluid.

The Role of Procalcitonin in the Diagnosis of Meningitis: A Literature Review

OBJECTIVE

To review the current published literature on the use of procalcitonin as a diagnostic and prognostic marker in adult patients with meningitis.

METHODS

We conducted a PubMed search to identify all relevant publications regarding the diagnostic and prognostic value of serum procalcitonin in patients with a known or suspected central nervous system infection. We also reviewed the bibliographies of all identified manuscripts in an attempt to identify additional relevant references.

RESULTS

A significant body of evidence suggests that serum procalcitonin has a promising role and can be a useful biomarker in the assessment of patients with meningitis.

CONCLUSIONS

Our literature review suggests that data on the role of Cerebrospinal Fluid (CSF) procalcitonin are limited, whereas serum procalcitonin (S⁻PCT) is probably a useful tool in the evaluation of patients with a known or suspected central nervous system infection and can help distinguish between bacterial and viral meningitis.

New diagnostic biomarker in acute diarrhea due to bacterial infection in children

BACKGROUND AND OBJECTIVES

Diarrhea is a major cause of morbidity and mortality in children, and diarrhea may be due to infection that is bacterial or non-bacterial. Differentiation between diarrhea from a bacterial or non-bacterial infection is not a simple task, and no single method is present to differentiate between these causes of diarrhea.To evaluate the diagnostic accuracy of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and procalcitonin (PCT) in the diagnosis of acute diarrhea due to bacterial infection.

PATIENTS AND METHODS

Case control study of forty children with bacterial infection diarrhea diagnosed by stool culture and CRP, 40 children with acute non-bacterial infection diarrhea and 30 age- and sex-matched healthy controls. Stool cultures, serum CRP, PCT and serum sTREM-1 were measured in all children on admission.

RESULTS

Children with acute bacterial infection diarrhea had a significant increase in the serum sTREM-1 and PCT levels on admission compared to patients with nonbacterial infection diarrhea and controls (26.3667 ± 16.8184 ng/ml vs 7.2267 ± 6.4174 ng/ml vs 6.7367 ± 5.6479 ng/ml and 39.9933 ± 22.5260 ng/ml vs 1.8533 ± 1.7123 vs 0.2840 ± 0.1208 ng/ml, respectively; P < 0.05). sTREM-1 demonstrated significantly higher sensitivity (93.7%) and specificity (94.3%) in the prediction of bacterial infection as a cause of acute diarrhea in children with an area under the receiver operator characteristic (ROC) curve (95% CI) of 0.94 (0.84-0.99) at a cutoff value of 12.4 ng/ml.

CONCLUSIONS

Both serum PCT and sTREM-1 are valuable in the early diagnosis of acute bacterial infection-induced diarrhea in children, and there was markedly higher diagnostic discriminatory power for sTREM-1.

Prevalence of MDR pathogens of bacterial meningitis in Egypt and new synergistic antibiotic combinations

The aim of this study was identifying bacterial pathogens involved in meningitis, studying their antibiotic resistance profiles, investigating the antibiotic resistance genes as well as evaluating the use of various antibiotic combinations. Antibiotic susceptibility tests were evaluated according to CLSI guidelines. Antibiotic combinations were evaluated by calculating the Fractional Inhibitory Concentration (FIC) index. A total of 71 bacterial isolates were recovered from 68 culture positive CSF specimens. Sixty five of these isolates (91.5%) were recovered from single infection specimens, while 6 isolates (8.4%) were recovered from mixed infection specimens. Out of the 71 recovered isolates, 48 (67.6%) were Gram-positive, and 23 (32.4%) were Gram-negative. Thirty one of the Gram positive isolates were S. pneumoniae (64.6%, n = 48). Out of the recovered 71 isolates; 26 (36.6%) were multidrug-resistant (MDR) isolates of which, 18 (69.2%) were Gram-negative and 8 (30.8%) were Gram-positive. All MDR isolates (100%) showed resistance to penicillin and ampicillin, however, they showed lower resistance to meropenem (50%), levofloxacin (50%), amikacin (48%), pipercillin-tazobactam (45.8%). Most common antibiotic resistance genes were investigated including: tem (21.1%), shv (15.8%), ctx-m (15.8%) coding for TEM-, SHV, CTX-M extended-spectrum beta-lactamases (ESBLs), respectively; aac(6')-I b(26.3%) coding for aminoglycoside 6'-N-acetyltransferase type Ib ciprofloxacin resistant variant; and qnrA (5.3%) gene coding for quinolone resistance. The DNA sequences of the respective resistance genes of some selected isolates were PCR amplified, analyzed and submitted to the GenBank database under the accession numbers, KX214665, KX214664, KX214663, KX214662, respectively. The FIC values for ampicillin/sulbactam plus cefepime showed either additive or synergistic effect against ten tested Gram-negative MDR isolates, while doxycycline plus levofloxacin combination revealed synergism against two MDR Gram-positive isolates. The results indicate high prevalence of antibiotic resistance among MDR isolates. Therefore, new guidelines should be implemented in Egypt to rationalize the use and avoid the misuse and abuse of antimicrobial agents.

Clinical, biological, and microbiological pattern associated with ventriculostomy-related infection: a retrospective longitudinal study

BACKGROUND

Our aim was to describe the pattern of ventriculostomy-related infection (VRI) development using a dynamic approach.

STUDY DESIGN

Retrospective longitudinal study.

METHODS

We analyzed the files of 449 neurosurgical patients who underwent placement of external ventricular drain (EVD). During the study period, CSF sampling was performed on a daily base setting. VRI was defined as a positive CSF culture resulting in antibiotic treatment. For VRI patients, we arbitrary defined day 0 (D0) as the day antibiotic treatment was started. In these patients, we compared dynamic changes in clinical and biological parameters at four pre-determined time points: (D-4, D-3, D-2, D-1) with those of D0. For all CSF-positive cultures, we compared CSF biochemical markers' evolution pattern between VRI patients and the others, considered as a control cohort.

RESULTS

Thirty-two suffered from VRI. Peripheral white blood cell count did not differ between D-4-D0. Median body temperature, CSF cell count, median Glasgow Coma Scale, CSF protein, and glucose concentrations were significantly different between D-4, D-3, D-2, and D0. At D0, 100 % of CSF samples yielded organisms in culture. The physician caring for the patient decided to treat VRI based upon positive CSF culture in only 28 % (9/32) of cases. In the control cohort, CSF markers' profile trends to normalize, while it worsens in the VRI patients.

CONCLUSIONS

We showed that clinical symptoms and biological abnormalities of VRI evolved over time. Our data suggest that VRI decision to treat relies upon a bundle of evidence, including dynamic changes in CSF laboratory exams combined with microbiological analysis.

Streptococcus pneumoniae invasive infections in Burkina Faso, 2007 to 2011

OBJECTIVE

We had for aim to determine the epidemiology of meningeal and lung invasive infections due to Streptococcus pneumoniae in Burkina Faso.

MATERIAL AND METHODS

We screened for S. pneumoniae with the usual bacteriology techniques and with real time polymerase chain reaction (rt-PCR) in 7917 samples of cerebrospinal fluid (CSF) and pleural fluid (PF) collected in the Ouagadougou Yalgado Ouedraogo Teaching Hospital, from 2007 to 2011.

RESULTS

S. pneumoniae was identified in 476 (6%) samples including 455 (5.7%) in CSF and 21 (0.3%) in PF. Sixty-seven percent of invasive infections occurred in patients 15 years of age or less, without any significant sex ratio difference. The infections occurred most frequently between January and August, with the first and most important peak between January and May (dry season) and the second peak between June and August (at the beginning of rain season). The introduction of rt-PCR proved the under diagnosing of invasive infections by usual bacteriological methods (latex agglutination assay and culture).

CONCLUSION

Invasive pneumococcal infections occur mainly in patients 15 years of age or less, without any difference in sex ratio and with peaks in the dry season. Vaccinal schedules should include all age ranges in Burkina Faso.

Prediction of bacterial meningitis based on cerebrospinal fluid pleocytosis in children

Children with cerebrospinal fluid pleocytosis are frequently treated with parenteral antibiotics, but only a few have bacterial meningitis. Although some clinical prediction rules, such as bacterial meningitis score, are of well-known value, the cerebrospinal fluid white blood cells count can be the initial available information. Our aim was to establish a cutoff point of cerebrospinal fluid white blood cell count that could distinguish bacterial from viral and aseptic meningitis. A retrospective study of children aged 29 days to 17 years who were admitted between January 1st and December 31th, 2009, with cerebrospinal fluid pleocytosis (white blood cell≥7μL(-1)) was conducted. The cases of traumatic lumbar puncture and of antibiotic treatment before lumbar puncture were excluded. There were 295 patients with cerebrospinal fluid pleocytosis, 60.3% females, medium age 5.0±4.3 years distributed as: 12.2% 1-3 months; 10.5% 3-12 months; 29.8% 12 months to 5 years; 47.5% >5 years. Thirty one children (10.5%) were diagnosed with bacterial meningitis, 156 (52.9%) viral meningitis and 108 (36.6%) aseptic meningitis. Bacterial meningitis was caused by Neisseria meningitidis (48.4%), Streptococcus pneumoniae (32.3%), other Streptococcus species (9.7%), and other agents (9.7%). cerebrospinal fluid white blood cell count was significantly higher in patients with bacterial meningitis (mean, 4839cells/μL) compared to patients with aseptic meningitis (mean, 159cells/μL, p<0.001), with those with aseptic meningitis (mean, 577cells/μL, p<0.001) and with all non-bacterial meningitis cases together (p<0.001). A cutoff value of 321white blood cell/μL showed the best combination of sensitivity (80.6%) and specificity (81.4%) for the diagnosis of bacterial meningitis (area under receiver operating characteristic curve 0.837). Therefore, the value of cerebrospinal fluid white blood cell count was found to be a useful and rapid diagnostic test to distinguish between bacterial and nonbacterial meningitis in children.

Canine C-Reactive Protein Measurements in Cerebrospinal Fluid by a Time-Resolved Immunofluorimetric Assay

In the current study, the quantification of C-reactive protein (CRP) in cerebrospinal fluid (CSF) of dogs using an adapted time-resolved immunofluorimetric assay (TR-IFMA) was investigated, as well as whether the assay could be used to detect the range of CRP concentrations found in different clinical situations. Intra- and interassay coefficients of variation were below 15% in all cases. The TR-IFMA measured the CRP values in a proportional and linear manner ( r = 0.99); also CRP concentrations measured in CSF and in serum were significantly correlated ( r = 0.80, P = 0.003). The limit of detection of the method was 7.1 × 10−6 mg/l. The assay was able to detect differences in CRP concentrations in CSF of dogs with inflammatory disorders compared with dogs with spinal cord compression or idiopathic epilepsy. In conclusion, TR-IFMA constitutes a very sensitive, precise, and accurate method for the measurement of CRP concentrations in CSF.