Clinical efficacy of convalescent plasma for treatment of COVID-19 infections: Results of a multicenter clinical study

Since Dec. 2019 the new coronavirus (SARS-CoV-2) has infected millions and claimed life of several hundred thousand worldwide. However, so far no approved vaccine or drug therapy is available for treatment of virus infection. Convalescent plasma has been considered a potential modality for COVID-19 infection. One hundred eighty-nine COVID-19 positive patients including 115 patients in plasma therapy group and 74 patients in control group, registered in the hospitals with confirmed COVID-19 infection, entered this multi-center clinical study. Comparison of outcomes including all-cause mortality, total hospitalization days and patients� need for intubation between the two patient groups shows that total of 98 (98.2 ) of patients who received convalescent plasma were discharged from hospital which is substantially higher compared to 56 (78.7 ) patients in control group. Length of hospitalization days was significantly lower (9.54 days) in convalescent plasma group compared with that of control group (12.88 days). Only 8 patients (7) in convalescent plasma group required intubation while that was 20 in control group. This clinical study provides strong evidence to support the efficacy of convalescent plasma therapy in COVID-19 patients and recommends this treatment for management of these patients. Clinical efficacy, immediate availability and potential cost effectiveness could be considered as main advantages of convalescent plasma therapy. © 2020 Elsevier Lt

Effect of sub-lethal doses of nisin on Staphylococcus aureus toxin production and biofilm formation

Staphylococcus aureus is one of the commonest food-borne pathogens that can cause gastroenteritis owing to having several enterotoxins. Also, biofilm formation can complicate infections caused by this microorganism. Nisin is a safe food bio preservative which is usually used as an agent to prevent pathogen growth; however, it is important to identify the exact impact of nisin on the growth of S. aureus and to determine the suitable concentration needed for elimination of this pathogen in food. In this study, after MIC determination of nisin against S. aureus ATCC 29213, this strain was treated with sub-MIC (1/2) of nisin (4 μg/ml) and transcript levels of toxin-encoding (hla, SEA, SEB, and SED) and biofilm-associated (fnb, ebpS, eno, and icaA) genes were determined using Quantitative Real-time PCR at 2, 8, and 24 h post exposure. All toxin genes were down-regulated following exposure to sub-MIC of nisin, whereas biofilm-associated genes were up-regulated. The expression levels of fnb and icaA in S. aureus were highest after 8 h (4.5-fold and 6.8-fold increase, respectively), while the expression levels of eno and ebpS genes were highest after 2 h (3.3 and 4.5-fold increase, respectively). According to these results, although transcriptional levels of toxin genes were reduced, sub-MIC concentrations of nisin could trigger the expression of biofilm-associated genes in S. aureus. This can further lead to bacteriocin tolerance such that even its higher concentrations cannot kill bacterial cells after exposure to sub-lethal doses. Therefore, it is pivotal to add appropriate concentrations of nisin to food products for preservation purposes. © 202

Global estimate of Neisseria meningitidis serogroups proportion in invasive meningococcal disease: A systematic review and meta-analysis

Using the PRISMA guideline, 102 studies were included in this study. The highest and the lowest proportion of N. meningitidis serogroups in invasive meningococcal disease (IMD) was for NmB with 48.5 (95 CI: 45�52) and NmX with 0.7 (95 CI: 0.3�1.7). Among the WHO regional offices, serogroup NmW with 57.5 (95 CI: 35�77.5) in Eastern Mediterranean, and NmZ with 0.1 (95 CI: 0�0.9) in America had the highest and the lowest proportion of N. meningitidis serogroups in IMD. NmC with 9.7 (95 CI: 5.6�16.2) and NmB with 9.5 (95 CI: 0.2�3.8) had the highest proportion in 1�4 and <1 year age groups, respectively. Our analysis showed that NmB had the highest proportion of N. meningitidis serogroups in IMD worldwide. However, proportion of N. meningitidis serogroups in IMD varied noticeably across countries and age groups. Therefore, establishing appropriate control guidelines depending on the geographical regions and age groups is essential for prevention of IMD. © 201

A survey of traditional Iranian food products for contamination with toxigenic Clostridium botulinum

Summary: This study aimed to determine the rate of Clostridium botulinum contamination in some traditional Iranian food products (cheese, kashk and salted fish) and evaluate the efficacy of the mouse bioassay method in detection of C. botulinum toxins in these foods. A total of 131 samples (57 cheese, 11 kashk and 63 salted fish) were collected and examined to determine the rate of contamination by C. botulinum. Standard monovalent anti-toxins were used to determine the types of toxin. C. botulinum bacteria were detected in 4.58% of the examined samples (1.52% of cheese and 3.06% of salted fish samples). While no contamination was detected in the kashk samples, C. botulinum types A and E were found to be dominant in cheese and salted fish samples, respectively. These results indicate—some traditional Iranian foods may be contaminated with different types of C. botulinum, and the consumption of these products, either raw or cooked, may contribute to food-borne intoxications. Keywords: Clostridium botulinum, Botulinum toxin, Traditional food

The reliability of rifampicin resistance as a proxy for multidrug-resistant tuberculosis: a systematic review of studies from Iran

In Iran, patients showing rifampicin (RIF) resistance detected by the Xpert® MTB/RIF assay are considered as candidates for multidrug-resistant tuberculosis (MDR-TB) treatment. Despite the fact that RIF resistance has been used as a proxy for MDR-TB, little is known about the proportion of isoniazid (INH) resistance patterns in RIF-resistant TB. We systematically searched MEDLINE, Embase, and other databases up to March 2017 for studies addressing the proportion of INH resistance patterns in RIF-resistant TB in Iran. The data were pooled using a random effects model. Heterogeneity was assessed using Cochran’s Q and I2 statistics. A total of 11 articles met the eligibility criteria. Data analysis demonstrated that 33.3 of RIF-resistant isolates from new TB cases and 14.8 of RIF-resistant isolates from previously treated cases did not display resistance to INH. The relatively high proportion of INH susceptibility among isolates with RIF resistance indicated that RIF resistance may no longer predict MDR-TB in Iran. Therefore, the detection of RIF resistance by the Xpert MTB/RIF assay will require complementary detection of INH resistance by other drug susceptibility testing (DST) methods in order to establish the diagnosis of MDR-TB. © 2017, Springer-Verlag GmbH Germany