Sensitivity of serology assay in Covid-19 diagnosis: does the antigen matter?

Since the spreading of Sar-CoV-2 in March 2020, many serologic tests have been developed to identify antibody responses. Indeed, different commercial kits are directed against different antigens and could utilise different methods thereby triggering confusion and criticism. Here, we compared two Food and Drug Administration (FDA)-approved automatized assays that detect IgG responses against spike or nucleocapsid protein of Sars-Cov-2 virus in 127 subjects among healthcare workers of IRCCS Policlinico San Donato (MI), Italy. We observed different kinetics of IgG responses, demonstrating the importance of timing of sampling to correctly interpret the results both for infection diagnosis and for epidemiologic studies. We observed that Anti-N response starts earlier than Anti-S1/S2 response but also decreases earlier, affecting the sensitivity of the tests at different time points. Combining two different assays, designed against different antigens, could reduce false negative results. Finally, we observed a patient who produced anti-nucleocapsid IgG, but not anti-spike IgG. In conclusion, we investigated antibody responses in Covid-19 disease, aiming to direct clinicians and laboratory scientists to correctly interpret serologic results by always paying attention to clinical history correlation, timing of sampling, methods and antigens used, to avoid false negative results and obtain relevant epidemiologic data.

Management of cytomegalovirus infection in pregnancy: is it time for valacyclovir?

BACKGROUND: Congenital cytomegalovirus (CMV) infection is the leading infectious cause of neurological impairment for which, currently, there are no approved antenatal treatment options. OBJECTIVES: The aim of this article was to summarize the available evidence on the use of valacyclovir during pregnancy to prevent and treat congenital CMV infection and disease. SOURCES: Two databases (PubMed and ClinicalTrial.gov) were reviewed. CONTENT: Six relevant documents were identified, namely one observational study, three clinical trials, two case reports. Most relevant findings were those from two clinical trials. A phase 2/3 placebo-controlled study showed a decrease of 71% (5 of 45 vs 14 of 47) in rate of CMV vertical transmission in women treated with 8 g/day valacyclovir following primary CMV infection in pregnancy. A phase 2, single-arm clinical trial, showed that 8 g/day valacyclovir administered to mothers of symptomatic infected foetuses increased the portion of asymptomatic neonates to 82% (34 of 41), compared with 43% (20 of 47) in untreated pregnancies from a historical cohort. IMPLICATIONS: Studies in favour of using valacyclovir during pregnancy for prevention and treatment of congenital CMV infection are emerging but are still few. Randomized clinical trials on large cohorts of patients investigating the efficacy on prevention and treatment of congenital CMV are required. Unfortunately, this will be probably not be feasible at least in the short period. In the meantime, data on the 'off label' use of valacyclovir for CMV in pregnancy could be collected within a multicentre observational study.

Quantification of neutrophil and monocyte CD64 expression: a predictive biomarker for active tuberculosis.

SETTING: QuantiFERON TB assay (QFT) is used to screen tuberculosis (TB) infection, but it cannot distinguish active TB from latent TB infection (LTBI).OBJECTIVE: To evaluate the quantitative expression of the high-affinity FCgamma receptor I (CD64) on neutrophils (NE) and monocytes (MO) in peripheral blood using flow cytometry, measured in antibody binding capacity (ABC) units as a predictive biomarker of TB.DESIGN: Fifty-two patients were enrolled (45 QFT-positive and 7 QFT-indeterminate). Cultures and molecular analyses were performed.RESULTS: Of the 45 QFT-positive patients, 29 were culture-positive (active TB) and 16 were negative (LTBI). The median NE CD64 ABC and MO CD64 ABC expression was significantly higher (P < 0.001) in culture-positive patients. The NE CD64 and MO CD64 area under the receiver operating characteristic curve values were respectively 0.948 (95%CI 0.838-0.992) and 0.989 (0.901-1.000). By setting the cut-off NE CD64 value at >2400 ABC or MO CD64 value >25 800 the assay sensitivity increased to 95.5% with 100% specificity and 100% positive predictive value. In the QFT-indeterminate group, five culture-positive cases had NE CD64 >2400 ABC or MO CD64 value >25 800; two culture-negative cases had lower values.CONCLUSION: The CD64 quantitative expression on peripheral blood cells may be used as a predictive biomarker for active TB.

Epidemiology of hepatitis D virus (HDV) infection in an urban area of northern Italy.

OBJECTIVES: The introduction of vaccination against hepatitis B initially reduced the number of HBV (hepatitis B virus) and HDV (hepatitis delta virus) infections, but the decreasing trend of HDV infection seems to have stopped. The aim of this study was to assess the prevalence of HDV infection in the general population living in the catchment area of Legnano Hospital in northern Italy. METHODS: Of the 22,758 subjects tested in 2007-2008, the 488 who were HBsAg (hepatitis B surface antigen)-positive [including 107 (21.9%) of non-Italian origin] were subsequently tested for anti-HDV antibodies. RESULTS: Of the 488 subjects who tested positive for HBsAg, 24 (4.9%) were anti-HDV positive, all aged between 30 and 60 years. The difference in prevalence between males (7.1%) and females (1.9%) was statistically significant (p < 0.05), but not that between Italian (5.0%) and non-Italian patients (4.7%). The differences in anti-HDV seropositivity between the patients with acute (0%) and chronic infections (6.3%), and between the incident (2.5%) and prevalent cases (7.4%), were not statistically significant, but there was a significant difference (p < 0.01) between those with asymptomatic (2.1%) and clinically symptomatic infections (10.3%). Intravenous drug abuse was the main source of infection. CONCLUSIONS: In the catchment area of our hospital, the prevalence of HDV infection does not seem to be due to patients of non-Italian origin, but to Italian patients who are not vaccinated against HBV and who survived the HDV epidemic of the 1970s and 1980s. Nevertheless, the increase in the number of immigrants from non-EU countries in recent years is soon likely to lead to a change in the epidemiology of HDV.

Epidemiology of HIV-1 subtypes in an urban area of northern Italy.

The distribution of the different subtypes of HIV varies from one region of the world to another. Subtype B is predominant in Europe and the USA, but there has been a gradual increase in non-B subtypes as a result of migration from regions where they are endemic, and this may have important implications for the control of HIV-1. The aim of this study was to assess the prevalence of HIV-1 subtypes in an urban area of northern Italy in the period 1997-2008. Forty-nine (12.2%; 95% CI, 9.00-15.40) of 401 patients investigated carried a non-B subtype, the prevalence of which was 7.7% (95% CI, 4.96-10.44) among native Italians and 55.3% (95% CI, 39.49-71.11) among non-Italians, 1.6% (95% CI, 0.00-3.81) among ex-intravenous drug addicts, 7.6% (95% CI, 1.21-13.99) among homosexual/bisexual men and 20.5% (95% CI, 14.83-26.17) among heterosexuals, 6.8% (95% CI, 3.37-10.23) among Italians infected as a result of sexual contacts in Italy, and 55.0% (95% CI, 33.20-76.80) among Italians infected abroad or by foreign partners. Overall prevalence increased from 2.9% (95% CI, 0.00-6.11) before 1993 to 23.0% (95% CI, 16.31-29.69) in the period 2001-2008. The results demonstrate that there has been an increase in non-B subtypes (especially sexually transmitted infections), particularly among patients infected abroad or by foreign partners.

[The preliminary assessment in the B-BS protocol as a tool for the discovery of job stress symptoms and contingencies: a method under experimentation by INAIL]. / L'assessment preliminare del protocollo B-BS come ausilio alla raccolta di dati sintomatici dello stress lavoro-correlato e all'individuazione delle contingenze che li sostengono: un metodo operativo in via di sperimentazione nelle sedi INAIL.

The proposed model is aimed at assessing work-related stress and consists of a preliminary phase during which the Organization is monitored, Indexes and stressors are defined, characterized and then weighted; existing symptoms (if any) are also identified. A 'Probability vs. Severity' Matrix is then built up as a result: these tasks can profitably be performed by a technical professional, typically the Responsible of the Safety and Health Committee. According to found evidences, a second phase, strictly based upon the application of psychosocial research tools, might be needed to investigate group of workers that resulted troublesome during the preliminary phase. The preliminary phase of investigation on organizational stressors and indexes can be easily and successfully integrated with the 'Safety Assessment' steps provided for the B-BS protocol, also aimed at monitoring the organizational wellbeing and consequently acting on the workers' behavior. The model has been specifically designed for Small and Medium Enterprises, with the global objective of preventing accidents at work due to misbehavior and distraction, by correctly and safely applying operational procedures and mutual relationships.

Seroprevalence and incidence of Toxoplasma gondii infection in the Legnano area of Italy.

The decreasing prevalence of anti-Toxoplasma antibodies in Europe has re-opened the question of the appropriateness of serological screening during pregnancy. A study of 3426 pregnant women, resident in the Legnano area of Italy, revealed that the IgG seroprevalence according to ELISA was 21.5%, and that of IgM according to ELISA and enzyme-linked fluorescent assay was 1.2% and 0.9%, respectively. The incidence of infection, estimated on the basis of IgG avidity, was 0.9%. These results confirm a decrease in the prevalence of IgG, but indicate a high incidence of infection, thus suggesting that screening for anti-Toxoplasma antibodies during pregnancy should be maintained.

[The Italian version of Nordic Musculoskeletal Standardized Questionnaire]. / Versione in lingua Italiana del questionario standardizzato autocompilabile Nordic IRSST per la rile vazione di disturbi muscoloscheletrici .

We translated into Italian the Nordic musculoskelethal questionnaire, as completed by Canadian IRSST with Authors' agreement in 2001, according to OMS recommendations. This translation involved the following items: aches and troubles of neck, dorsal region, low back, shoulders, elbows, hands and wrists, hips and thighs, ankles and feet in the last 12 months. The questionnaire was then submitted to reliability and stability tests. The Italian version of the questionnaire, already used in different languages, proved to be suitable and reliable also for self administration.

[An example of the evaluation of risks of repeated movements in pottery plants located in western Liguria]. / Un esempio di valutazione del rischio da movimenti ripetuti in aziende del comparto ceramico del ponente ligure.

Pottery manufacturing is typical in western Liguria and it represents one of the most important economical resources of this area. The major part of manufacturers are handicrafts, although some bigger firms have developed industrialized production cycles. Both types of productions, however, require hand work at almost all levels of processing. Most workers are women and a significant part of these are affected by Carpal Tunnel Syndrome. INAIL (Direzione Regionale Liguria) carries on a dedicated program for employers' insurance and Health & Safety implementation but--in order to do so--INAIL needs to achieve more knowledge about risk factors in this field. The aim of this study was to assess CTD risk in two pottery industries located in Albisola: in particular, two productions Cycles equipped with assembly lines have been investigated. The method used for risk assessment was OCRA Index (OCcupational Repetitive Actions), adapted to be applied to pottery industries.

Use of simulated blood cultures for antibiotic effect on time to detection of the two blood culture systems BacT/ALERT and BACTEC 9240.

To avoid the influence of pre-analytical steps, this study was performed using sterile blood spiked with defined loads of microorganisms as inoculum. Time-to-Detection (TTD) was evaluated for the most frequently encountered bacteria comparing two commercially available blood culture systems, BD BACTEC 9240 (Becton Dickinson) and BacT/ALERT (Organon Teknika). The effect of the most widely used antibiotics on TTD was evaluated on both systems. TTD was measured with antibiotics at their trough and at increasing concentrations. The results show that the BACTEC PLUS system recovers more pathogens with shorter time to detection than the BacT/ALERT FAN system when beta-lactam antibiotics (Ampicillin, Cefotaxime) are present at their respective trough concentration corresponding to parenteral therapy. The two systems seem to be equally efficient when Gentamicin, Ciprofloxacin and Trimethoprim/sulfamethoxazole are used; in the case of Vancomycin, BACTEC seems more effective than BacT/ALERT.

Life cycle of Ixodes (Ixodes) loricatus (Acari: Ixodidae) under laboratory conditions.

The life cycle of Ixodes (Ixodes) loricatus Neumann, reared in the laboratory, is described. Engorged females collected from opossums trapped in the states of Minas Gerais and São Paulo, Brazil, which were used to start the laboratory colonies, were designated as BMG and CSP, respectively. Larval and nymphal ticks from both colonies fed separately on Rattus norvergicus Berkenhout or Calomys callosus Rengger, whereas Didelphis marsupialis L and Didelphis albiventris Lund were used as hosts for BMG and CSP adults, respectively. Biological and developmental data obtained from ticks of both the BMG and CSP colonies that were reared separately for two consecutive generations were compared. The percentage of fed or molted ticks reared on C. callosus was higher than that recorded for ticks fed on R. norvergicus in the majority of the observations. Despite significant differences among several of the biological parameters, the pattern of the life cycles of the two tick colonies was similar. Results indicated that the mean life cycle duration of I. (I.) loricatus was approximately 7 mo from parental oviposition to the occurrence of F1 eggs, regardless of geographic origin or host species.

Epidemiology of urogenital infections caused by Chlamydia trachomatis and outline of characteristic features of patients at risk.

A study of Chlamydia trachomatis infection was conducted in two stages on 15,656 subjects at urogenital clinics of the Faculty of Medicine and Surgery at La Sapienza University in Rome, the S. Anna Hospital in Turin, and the Niguarda Hospital in Milan. The overall incidence of the disease was 6.4% in patients examined throughout the whole study period. The rate of positive cases was 5.8% for the 5270 patients examined up to 1990, and 6.7% for the 10,386 patients examined from 1990 to 1992, showing an increasing trend. There was a much higher positivity rate in men (9.8%) than in women (6.0%); the difference was statistically significant. Of all patients, 60%, were asymptomatic. In symptomatic patients, C. trachomatis was present in 18.5% of cases of non-gonococcal urethritis and in 12.8% of cases of salpingitis. The highest incidence of C. trachomatis infection was in women who had begun sexual activity at an early age, (under 25 years in age), had several sexual partners and used intra-uterine contraceptive devices or spermicides or both.

[Detection of Chlamydia trachomatis in urine samples. Possibility of a non-invasive screening]. / Ricerca di Chlamydia trachomatis in campioni di urine. Possibilità di uno screening non invasivo.

In clinic practice urethral specimens from a big proportion of patients are inadequate or swabbing if not undertaken at all because for the discomfort experienced. Moreover, such an experience sometimes discourages patients for reattending. It is clear that having a urine sample from patients is incomparably preferable to having an inadequate urethral swab or none. 250 women attending our gynecology clinic had a urinary sample (20 ml first-voided urine minimum 4-hours from prior menstruation) analysed with an enzyme immunoassay (IDEIA-Dako) for the detection of Chlamydia trachomatis. They also had sample taken from cervix, and urethra for testing with IDEIA. The urinary samples, compared with urethral samples, showed a optimal correspondence to final results. It is concluded that the urinary samples could be used for screening programs to detect Chlamydia trachomatis.

A study of the incidence of urogenital Chlamydia trachomatis in patients attending specialized departments of Rome, Milan and Turin, Italy.

A study of Chlamydia trachomatis was conducted in 5270 subjects seen at clinics of the Faculty of Medicine and Surgery at La Sapienza University in Rome, the S. Anna Hospital in Turin, and the Provincial Maternity Hospital Institute in Milan. In these areas, C. trachomatis was present in 5.8% of the cases examined; in addition it was present with statistically significant frequencies in cases of salpingitis (49.1) and epididymitis (21.7). It may also be found in cases of extrauterine pregnancy, sterility and abortion. Those most affected were women who had begun their sexual activity at an early age, were under 25, had several sexual partners and who used the coil and/or spermicides. A routine check for C. trachomatis should be considered for those women with those risk factors.

Humoral circulatory immune response to Gardnerella vaginalis.

Strain-specific circulating immunoglobulin G and/or M was detected by enzyme-linked immunosorbent assay and immunofluorescence test by using Formol-treated suspensions of Gardnerella vaginalis from 28 women with overt vaginitis but only three symptom-free subjects among 43 otherwise healthy women found to be colonized by G. vaginalis. Analogous but less stringent strain specificity patterns were elicited by immunization of BALB/c mice.

[Chlamydia and pharyngotonsillitis in childhood]. / Chlamydia e faringotonsillite nell'infanzia.

The aim of this study was to evaluate the role of Chlamydia trachomatis in pharyngeal infections in childhood. 200 children, aged 1 month to 12 years, with and without symptoms of pharyngitis were examined for CT. Swabs were taken from the oropharynx and tonsillar areas for direct fluorescent antibody assay. 12% of the patients and 4% of the control subjects were positive for CT. Group A Streptococcus was not isolated from any patient or control subject positive for CT. In positive cases we extended the research to relatives. The treatment for positive cases was erythromycin and it eradicated CT in 80% of our patients. A new strain of Chlamydia, called TWAR, showing cross-reactivity with CT, has been isolated. Therefore further research should be carried out to discover if micro-organisms considered CT up to now, do belong or not to TWAR strain. Long term studies in children will be helpful in further defining the role of Chlamydia, trachomatis or TWAR, as a cause of pharyngitis.