Methicillin-resistant Staphylococcus aureus screening in healthcare workers: should a new protocol be introduced?

Background: In recent times, emerging resistance to majority of antibiotic classes seen in Methicillin-resistant Staphylococcus aureus (MRSA) isolates is of concern in hospital-acquired infection. MRSA carriage by healthcare workers (HCWs) has been documented to be as high as 50% in some studies. Higher carrier rate increases the risk of developing active infection as well as transmission of infection to the patients. The study aims to establish a relationship between MRSA carrier rate and healthcare workers of a tertiary care hospital in Pune and understand the need for screening regimens, based on the outcome.Methods: A cross-sectional study including health care workers from a tertiary care hospital working in different clinical departments was carried out. Data was collected by taking samples of nasal swabs of 115 HCWs and inoculated immediately on blood agar. Culture plates were incubated at 37°C for 24 hours and colonies were tested by routine diagnostic techniques. Antibiotic sensitivity was tested using cefoxitin discs on Mueller Hinton medium.Results: Prevalence of Staphylococcus aureus carriage was reported in 19 out of 115 (16.52%) healthcare workers, of which 63.2% were MRSA and 36.8% were MSSA. Prevalence of MRSA among Orthopaedic surgeons and General surgeons showed a carrier rate of 25% and 18.2% respectively. Nurses had a prevalence rate of 0.39 %. Overall prevalence of MRSA carriage in healthcare workers was reported to be 10.4%Conclusions: MRSA carriage among HCWs at the hospital is considerably high. The high prevalence of MRSA carriage emphasizes the need for stringent hospital infection control and regular screening regimen of HCWs.

TSHB R75G is a founder variant and prevalent cause of low or undetectable TSH in Indian Jews

Objective: Bi-allelic loss-of-function mutations in TSHB, encoding the beta-subunit of TSH, cause congenital non-goiterous hypothyroidism. Homozygosity for the TSHB p.R75G variant, previously described in South Asian individuals, does not alter TSH function, but abrogates its detection by some immune-detection-based platforms, leading to erroneous diagnosis of hyperthyroidism. We set out to identify and determine carrier rate of the p.R75G variant among clinically euthyroid Bene Israel Indian Jews, to examine possible founder origin of this variant worldwide and to determine phenotypic effects of its heterozygosity. Design: Molecular genetic studies of Bene Israel Jews and comparative studies with South Asian cohort. Methods: TSHB p.R75G variant tested by Sanger sequencing and RFLP. Haplotype analysis in the vicinity of the TSHB gene performed using SNP arrays. Results: Clinically euthyroid individuals with low or undetectable TSH levels from three apparently unrelated Israeli Jewish families of Bene Israel ethnicity, originating from the Mumbai region of India, were found heterozygous or homozygous for the p.R75G TSHB variant. Extremely high carrier rate of p.R75G TSHB in Bene Israel Indian Jews (~4%) was observed. A haplotype block of 239.7kB in the vicinity of TSHB shared by Bene Israel and individuals of South Asian origin was detected. Conclusions: Our findings highlight the high prevalence of the R75G TSHB variant in euthyroid Bene Israel Indian Jews, demonstrate that heterozygosity of this variant can cause erroneous detection of subnormal TSH levels, and show that R75G TSHB is an ancient founder variant, delineating shared ancestry of its carriers.

Throat culture screening for Beta-haemolytic streptococci among schoolboys in Saudi Arabia

Thistudy was designed to estimate the carrier rate of beta-haemolytic streptococci among 972 primary-school boys in a high-altitude area of Saudi Arabia, and its association with social class, crowding index and body mass index, and also to determine the seasonal variation of infection. A carrier rate of 13.1% for beta-haemolytic streptococci was detected. The carrier rate was significantly higher in spring than in winter. The association between streptococcal infection and social class, crowding index, or body mass index was statistically not significant. The low prevalence of streptococcal infection might be attributed to the high altitude but further studies are needed to determine whether this is the case

Clinical Implementation of Expanded Carrier Screening in Pregnant Women at Early Gestational Weeks: A Chinese Cohort Study

Demands for expanded carrier screening (ECS) are growing and ECS is becoming an important part of obstetrics practice and reproductive planning. The aim of this study is to evaluate the feasibility of a small-size ECS panel in clinical implementation and investigate Chinese couples’ attitudes towards ECS. An ECS panel containing 11 recessive conditions was offered to Chinese pregnant women below 16 gestational weeks. Sequential testing of their partners was recommended for women with a positive carrier status. The reproductive decision and pregnancy outcome were surveyed for at-risk couples. A total of 1321 women performed ECS successfully and the overall carrier rate was 19.23%. The estimated at-risk couple rate was 0.83%. Sequential testing was performed in less than half of male partners. Eight at-risk couples were identified and four of them performed prenatal diagnosis. Our study demonstrated that a small-size ECS panel could yield comparable clinical value to a larger-size panel when the carrier rate of the individual condition is equal or greater than 1%. In addition, more than half of male partners whose wives were carriers declined any types of sequential testing possibly due to a lack of awareness and knowledge of genetic disorders. Genetic education is warranted for the better implementation of ECS.

Effect of Haemophilus influenzae Type b Vaccination on Nasopharyngeal Carriage Rate in Children, Tehran, 2019

Background. Haemophilus influenzae (H. influenzae) strains, which commonly reside as commensals within the human pharynx and can remain as an asymptomatic carrier, but become invasive leading to pneumonia, septic arthritis, or meningitis. The Pentavac (pentavalent vaccine, manufactured by India, SII (DTwP-HepB-Hib)) was introduced to the Iranian National Immunization Plan in November 2014. The aim of this study is to investigate H. influenzae type b (Hib) carrier rate among children under 6 years old in Tehran. Methods. This cross-sectional study was performed on 902 children including vaccinated/unvaccinated in the age of 6 months to 6 years, in Tehran. Sampling was performed from July 2019 to September 2019. Nasopharyngeal samples were taken from children by sterile swab. The PCR method was used to extract DNA. Then, all H. influenzae isolates were initially confirmed by molecular tests. BexA was used to distinguish typeable H. influenzae strains from nontypeable Haemophilus influenzae (NTHi). Results. A total of 902 children were enrolled in the study: 452 were female (51%). H. influenzae carriage rate was 267 (29%), of that 150 samples (16.6%) were typeable. The nasopharyngeal Hib carrier rate in the children was 2.6% (24/902). 262 cases did not receive Hib vaccine. Analysis in nonnursery’s children aged 4 to 6 (unvaccinated) years showed that the lower educational level of father, mother, and family number correlated with increased odds of colonization of children with Hib. Conclusion. Our findings showed a significant decrease (60%) in the overall Hib nasopharyngeal carriage in healthy children under six years after 5 years after the start of Hib vaccination.

Carrier Screening of 400 Variations Related 11 Recessive Diseases in the Daur Ethnicity in China

Background: Single gene disorders are common diseases that cause birth defect. Carrier screening is an effective method to reduce the affected children with single gene disorders. However, incidence rates and carrier positive rates vary among ethnic groups. Results: In the present study, four hundred alleles associated with 11 recessive disease were detected in the Daur ethnicity of China. Among the 246 individuals, 25 individuals were identified as heterozygous carriers of at least one for 11 recessive disorder, carrier rate was 10.16%. A total of 19 females were carrier positive among 143 individuals with a 13.29% positive rate, however, only 6 out 103 males were carrier positive with a 5.83% positive rate. The most common in the Daur was HLD (2.85%) and congenital hearing loss (2.85%), followed by CAH (2.44%), PKU (1.22%), SMA (0.41%), MMA (0.41%), and X-linked ichthyosis (0.41%). Conclusions: These results estimated the distribution of carrier frequencies in the Daur, and showed that several of these diseases may be considered for inclusion in carrier screening in the Daur population. Further large-scale study should be performed to identified the results.

The role of MEFV gene in COVID 19 disease, as a protective factor

Background In early 2020, an outbreak of pneumonia caused by a novel coronavirus became pandemic. This study evaluates the potential immune-genetically role of MEFV gene mutations in COVID 19 patients. Methods 50 COVID 19 PCR positive patients who were hospitalized in COVID 19 referral centers between 1st of March to 30th of April in 2020 were evaluated for MEFV gene mutations using ARMS PCR and Sanger sequencing. Results MEFV gene mutations were found in 6 (12%) of the patients. No homozygote or compound heterozygote forms were detected. The total mutant allele frequency was 6%. The carrier rate was 12% which is significantly lower than previously studied rate of 25%. The most common MEFV variant was E148Q in 3 (6%). There was no mutant variant of MEFV gene among the expired patients. None of the MEFV gene mutant patients had FMF symptoms or positive family history of FMF disease. Conclusion Considering the high carrier rate of MEFV gene mutations in the eastern Mediterranean region and a significantly lower prevalence of these mutations in COVID 19 patients, it seems that MEFV gene mutations may have a protective role in incidence of the disease.

NDM-1-Positive K. pneumoniae at a Teaching Hospital in Southwestern China: Clinical Characteristics, Antimicrobial Resistance, Molecular Characterization, Biofilm Assay, and Virulence

Background. The emergence of the NDM-1-positive Klebsiella pneumoniae (K. pneumoniae) strains has led to limited therapeutic options for clinical treatment. Understanding the clinical characteristics, antimicrobial resistance, biofilm assay, and the virulence genes of these isolated strains is of great significance. Methods. The polymerase chain reaction (PCR) was used to screen isolated NDM-1-positive K. pneumoniae. The clinical information of the patients was collected from medical records. The NDM-1-positive K. pneumoniae isolates were subjected to antimicrobial susceptibility testing and multilocus sequence typing. Sixty strains of NDM-1-negative K. pneumoniae isolated during the same period were collected as the control group for the virulence analysis. The virulence phenotype of the strains was preliminarily evaluated by the string test and crystal violet semiquantitative biofilm formation experiment. PCR combined with gene sequencing was used to detect common high toxicity capsule genes (K1, K2, K5, K20, K54, and K57) and common virulence-related genes (entB, ybtS, ureA, ycf, WabG, FimH, uge, iutA, KfuB, aerobactin, rmpA, magA, Alls, IrnN, and VatD). Results. In the 30 nonduplicated NDM-1-positive K. pneumoniae isolates, 43.33% (13/30) of the patients had a history of a stay in the neonatal intensive care unit (NICU). All of the isolates exhibited multidrug resistance. Nine STs were identified, 77% (10/13) strains from the NICU were ST11. The NDM-1-positive K. pneumoniae string tests were all negative, and 35% (21/60) NDM-1-negative K. pneumoniae were positive. The ratios of NDM-1-positive K. pneumoniae isolates biofilm formation ability according to strong, medium, and weak classification were 67%, 23%, and 10%, respectively. NDM-1-negative K. pneumoniae isolates were 60%, 25%, and 15%, respectively. There was no statistical difference between the two groups (t = 0.61, P=0.2723). The virulence-associated genes with more than 80% of detection rates among the 30 NDM-1-positive K. pneumoniae isolates included entB (100%, 30/30), ybtS (93.33%, 28/30), ureA (90%, 27/30), ycf (83.33%, 25/30), and wabG (90%, 27/30). KfuB and iutA were detected at prevalence of 3.33% and 13.33%. vatD, allS, iroN, aerobactin, and rmpA were not detected. In the NDM-1-negative K. pneumoniae, all other 14 virulence genes except VatD were detected. After statistical analysis, FimH, WabG, ycf, iutA, kfuB, aerobactin, rmpA, and Alls virulence genes, P<0.005, there was a statistical difference. Conclusion. NDM-1-positive K. pneumoniae exhibited multidrug resistance, MLST typing is mainly ST11, there is small clonal dissemination in the NICU in the hospital, and the NDM-1-positive K. pneumoniae virulence genes carrier rate is lower than the NDM-1-negative K. pneumoniae virulence genes carrier rate.

Large-scale screening of thalassemia in Ji’an, P.R. China

Background: To evaluate the prevalence of alpha- and beta-thalassemia in Ji'an City, Jiangxi Province, 28,941 people in the region were genetically screened to identify various thalassemia genotypes. Methods: High-throughput amplicon sequencing and gap-PCR was used to screen 301 thalassemia alleles in 28,941 people in the region. Pregnant women were the focus of this screening, and if a pregnant woman harbored mutations in a thalassemia-inducing gene, her spouse was also genetically tested. Results: Of the participants, 2,380 people were carriers of thalassemia, with at least one thalassemia allele, including 1,742 alpha-thalassemia carriers, 686 beta-thalassemia carriers and 48 composite alpha- and beta-thalassemia carriers. The total carrying rate of thalassemia in Ji'an was 8.22%, and the carrying rates of alpha- and beta-thalassemia were 6% and 2.37%, respectively. In addition, the first measured carrier rate of composite alpha- and beta-thalassemia in Ji'an was 0.17%. According to the geographical distribution of the 1,742 alpha -thalassemia carriers, the city with the highest carrier rate was Suichuan, followed by Wan’an and Taihe. According to the geographical distribution of the 686 beta-thalassemia carriers, the top three cities with high carrier rates were Suichuan, Wan'an and Xiajiang, sequentially. Conclusions: This research emphasizes the importance of large-scale population screening and that comprehensive molecular epidemiology data are necessary for the proper prevention and treatment of thalassemia. The epidemiological data updated in this research may enable the local government to focus on the severity of this disease and determine a method for effective resource allocation under limited resource conditions.