Serotype distribution, antibiotic resistance, multilocus sequence typing, and virulence factors of invasive and non-invasive Streptococcus pneumoniae in Northeast China from 2000 to 2021.

Streptococcus pneumoniae infection is a major public health concern with high morbidity and mortality rates. This study aimed to evaluate the serotype distribution, antimicrobial resistance changes, clonal composition, and virulence factors of S. pneumoniae isolates causing pneumococcal disease in northeast China from 2000 to 2021. A total of 1,454 S. pneumoniae isolates were included, with 568 invasive strains and 886 non-invasive strains. The patients from whom the S. pneumoniae were isolated ranged in age from 26 days to 95 years, with those ≤ 5 years old comprising the largest group (67.19%). 19 F, 19 A, 23 F, 14, and 6B were the most common serotypes, of which 19 A and 19 F were the main serotypes of invasive and non-invasive S. pneumoniae, respectively. CC271 was the most common multilocus sequence type. Serotype 14 had the lowest expression of cbpA, rrgA, and psrP genes, but expression levels of 19 A and 19 F genes were similar. All isolates were sensitive to ertapenem, moxifloxacin, linezolid, and vancomycin but highly resistant to macrolides, tetracyclines, and cotrimoxazole. Simultaneous resistance to erythromycin, clindamycin, tetracyclines, and trimethoprim/sulfamethoxazole was common pattern among multidrug-resistant isolates. Non-invasive S. pneumoniae had higher resistance to ß-lactam antibiotics than invasive strains. 19 A and 19 F were the main strains of penicillin-resistant S. pneumoniae. The resistance rate of ß-lactam antibiotics decreased from 2017 to 2021 compared to previous periods. Including PCV13 in the national immunization program can reduce the morbidity and mortality rates of pneumococcal disease effectively.

Serological and molecular investigation of B (A) blood group and its transfusion strategy: A case report / 中国输血杂志

【Objective】 To study the serological and genetic characteristics of a case of B(A) blood group. 【Methods】 Serological and genetic ABO blood group typing were used to analyze the ABO subtype and family inheritance of the probands and her 8 family members. The B(A) blood type sample was used as the blood recipient, and the B-type and O-type donors were selected for cross-matching using microcolumn gel anti-human globulin method to evaluate the blood transfusion strategy. 【Results】 5 out of 9 family blood samples were B(A) phenotype, carrying B(A)04 allele. Among them, 1 was B(A)04/O1 type, and 4 were B(A)04/B type. The primary blood matching of B(A) blood type samples with type B and O recipients were all negative. 【Conclusion】 A total of 5 cases of B(A)04 blood type were found in this family investigation, and there were differences in serological manifestations. Washed RBCs with B and O type can be used for B(A) blood type transfusion, and type B suspended RBCs can be considered in case of emergency.

ABO, Rhesus, and Kell Antigens, Alleles, and Haplotypes in West Bengal, India.

BACKGROUND: Few studies have documented the blood group antigens in the population of eastern India. Frequencies of some common alleles and haplotypes were unknown. We describe phenotype, allele, and haplotype frequencies in the state of West Bengal, India. METHODS: We tested 1,528 blood donors at the Medical College Hospital, Kolkata. The common antigens of the ABO, Rhesus, and Kell blood group systems were determined by standard serologic methods in tubes. Allele and haplotype frequencies were calculated with an iterative method that yielded maximum-likelihood estimates under the assumption of a Hardy-Weinberg equilibrium. RESULTS: The prevalence of ABO antigens were B (34%), O (32%), A (25%), and AB (9%) with ABO allele frequencies for O = 0.567, A = 0.189, and B = 0.244. The D antigen (RH1) was observed in 96.6% of the blood donors with RH haplotype frequencies, such as for CDe = 0.688809, cde = 0.16983 and CdE = 0.000654. The K antigen (K1) was observed in 12 donors (0.79%) with KEL allele frequencies for K = 0.004 and k = 0.996. Conclusions: For the Bengali population living in the south of West Bengal, we established the frequencies of the major clinically relevant antigens in the ABO, Rhesus, and Kell blood group systems and derived estimates for the underlying ABO and KEL alleles and RH haplotypes. Such blood donor screening will improve the availability of compatible red cell units for transfusion. Our approach using widely available routine methods can readily be applied in other regions, where the sufficient supply of blood typed for the Rh and K antigens is lacking.

Advances in Blood Typing.

The clinical importance of blood group antigens relates to their ability to evoke immune antibodies that are capable of causing hemolysis. The most important antigens for safe transfusion are ABO and D (Rh), and typing for these antigens is routinely performed for patients awaiting transfusion, prenatal patients, and blood donors. Typing for other blood group antigens, typically of the Kell, Duffy, Kidd, and MNS blood groups, is sometimes necessary, for patients who have, or are likely to develop antibodies to these antigens. The most commonly used typing method is serological typing, based on hemagglutination reactions against specific antisera. This method is generally reliable and practical for routine use, but it has certain drawbacks. In recent years, molecular typing has emerged as an alternative or supplemental typing method. It is based on detecting the polymorphisms and mutations that control the expression of blood group antigens, and using this information to predict the probable antigen type. Molecular typing methods are useful when traditional serological typing methods cannot be used, as when a patient has been transfused and the sample is contaminated with red blood cells from the transfused blood component. Moreover, molecular typing methods can precisely identify clinically significant variant antigens that cannot be distinguished by serological typing; this capability has been exploited for the resolution of typing discrepancies and shows promise for the improved transfusion management of patients with sickle cell anemia. Despite its advantages, molecular typing has certain limitations, and it should be used in conjunction with serological methods.

Serological and molecular identification of Legionella spp. isolated from water and surrounding air samples in Italian healthcare facilities.

BACKGROUND: Legionella is an intracellular microorganism living in natural and artificial aquatic environments. Although its transmission to humans is linked to the inhalation of contaminated aerosols, there is no validated air sampling method for the control and prevention of the disease. The aim of the present study was to provide more information on the distribution of Legionella spp. in indoor environments and to determine whether the same Legionella strains are isolated from air and water samples. METHODS: Ten healthcare facilities located in seven regions of Italy were enrolled. The serological typing of Legionella spp. from water samples and the surrounding air by active and passive sampling was assessed using polyvalent and monovalent antisera. Subsequently, the strains identified as Legionella pneumophila (Lpn) underwent molecular typing by sequence-based typing (SBT) using seven genes (flaA, pilE, asd, mip, mompS, proA, and neuA). The allelic profile number was assigned using the European Working Group for Legionella Infections-SBT database. RESULTS: Lpn serogroup 6 was the most prevalent serogroup; it was found simultaneously in the air and water samples of three different healthcare facilities. In the remaining seven hospitals, Lpn serogroups 1, 6, 7, 9, and 12 were isolated exclusively from water samples. The molecular investigation showed that Lpn strains in the water and air samples of each positive healthcare facility had the same allelic profile. Strains, identified as sequence types (STs) 728 and ST 1638+ST 1324, were isolated in two respective healthcare facilities, and a new strain, identified as ST 1989, was obtained in one healthcare facility. CONCLUSION: The application of the SBT method allowed to verify the homology among Legionella strains from water samples and the surrounding air. The results showed that the same Lpn strains were present in the air and water samples, and a new Legionella strain was identified.

A new non-expressed allele HLA-A*03:168N, identified by serological and sequence-based typing in a voluntary Norwegian hematopoietic stem cell donor.

HLA-A*03:168N differs from HLA-A*03:01:01 by a single nucleotide substitution resulting in a coding change Y27X.

Two - step PCR - SSP genotyping for HLA - A locus and its comparison with serological typing results / 中国法医学杂志

Objective To identify routine forensic samples by genotyping method for HLA - A locus. Method A two - step PCR - SSP method was established. The first step is amplification with a pair of primers specific for all HLA - A alleles, the second step is amplification with primers specific for HLA - A30, A31, A33 respectively, using the first step amplification product as template. Secondly amplified PCR products were genotyped by electro-phoresis. Results 100 blood stains with a serological typing result of HLA - A30, A31 and A33 were tested with this method. The discrepancy rate between serological and genetic typing was 29%. Seminal stains, salivary stains reserved for 2 years and blood stains reserved for 18 years in room temperature gave satisfactory results. Conclusions It is better to replace serological typing by genetic typing. A two - step PCR - SSP genotyping method can be applied to forensic samples.

Comparison of HLA-Cw Typing by Serology and PCR-SSP in the Korean Population / 대한임상병리학회지

BACKGROUND: Using the classical serological methods, the HLA-Cw typing resulted in a high frequency of Cw blank because of the lack of suitable antisera coupled with low cell surface expression. Recent data on association between graft-versus-host disease and serologically undetectable HLA-Cw mismatches in bone marrow transplantation (BMT) facilitate the investigations into the biological role of HLA-Cw and more reliable HLA-Cw typing. METHODS: We performed the HLA-Cw DNA typing using PCR-SSP technique with sequence-specific primers of 22 pairs in 150 Koreans (79 organ transplant recipients, 71 healthy potential donors). These results were compared with those of serological HLA-Cw typing, which had been performed by complement-dependent microlymphocytotoxicity technique using Terasaki Tissue typing tray. RESULTs: Comparison between serological and PCR-SSP typing revealed a discrepancy rate of 24.0% (36/150). The majority of total discrepancies (29/36, 80.6%) were due to antigens that were not detected serologically and these antigens consisted of mainly Cw*12 and Cw*15. In five cases, no Cw allele was detected by DNA typing, whereas serological typing showed antigens and different antigen assignments between two methods were found in three cases. Of 66 individuals typed serologically with one blank, 66.6% (44 cases) were confirmed to be homozygous, whereas an additional Cw allele was found in remaining 22 cases using the PCR-SSP technique. In the case of the serologically undetectable HLA-Cw blank antigens, the gene frequencies of Cw*12 and Cw*15 were 6.4% and 2.8%, respectively. CONCLUSIONS: These results indicated that serological typing is insufficient for accurate HLA-Cw typing. DNA typing using PCR-SSP technique appears a reliable and practical method for accurate HLA-Cw typing which can contribute to the evaluation of the biological role of the HLA-Cw in transplantation.

Analysis for misassignments of HLA-B homozygotes by serology and detection for HLA-B expression variants / 中国免疫学杂志

Objective:To find the discrepancies caused by HLA B gene variants in HLA B antigen homozygotes which were typed again by DNA method.Methods:75 blood samples assigned HLA B homozygotes by serology were typed and detected HLA B expression variants by PCR SSP.Results:The 12 samples had been assigned the second alleles by DNA method in 75 HLA B homozygotes by serology.One out of 12 samples was identified expression variant by PCR SSP.The null allele was caused by the insertion of an extra cytosine at the beginning of exon 4.Conclusion:HLA B gene typing by PCR SSP will be the use of supplement to serology.The expression variant detection by PCR SSP will improve accuracy for tissue typing and benefit clinical application.