BackgroundThis study was undertaken to determine the susceptibility profile and the mechanism of antibiotic resistance in Group B streptococcus (GBS) isolates detected in vaginal and rectal swabs from pregnant women attending Dr George Mukhari Academic Hospital, a University Teaching Hospital in Pretoria, South Africa.MethodsThe samples were collected over an 11-month period, cultured on selective media (colistin and nalidixic acid agar and Todd-Hewitt broth), and GBS positively identified by using different morphological and biochemical tests. The susceptibility testing was done using the Kirby–Bauer and E test methods according to CLSI guidelines 2012. The D test method was used for the detection of inducible clindamycin resistance. Multiplex PCR with specific primers was used to detect different genes coding for resistance.ResultsOut of 413 samples collected, 128 (30.9 %) were positive with GBS. The susceptibility testing revealed that 100 % of isolates were sensitive to penicillin, ampicillin, vancomycin and high level gentamicin. Erythromycin and clindamycin resistance was 21.1 and 17.2 %, respectively, in which 69 % had harboured constitutive macrolide, lincosamide and streptogramin B (MLSB), 17.4 % had inducible MLSB. The M and L phenotypes were present in 6.8 % each. The methylation of target encoded by ermB genes was the commonest mechanism of resistance observed in 55 % of isolates, 38 % of isolates had both ermB and linB genes and efflux pump mediated by mefA genes was also distributed among the isolates.ConclusionsThe study reaffirmed the appropriateness of penicillin as the antibiotic of choice for treating GBS infection. However it identified the challenges of resistance to macrolides and lincosamides used as alternative drugs for individuals allergic to penicillin. More GBS treatment options for penicillin allergic patients need to be researched on.

The distribution of capsular polysaccharide (CPS) types and subtypes (serovariants) among 121 group B streptococcus (GBS) strains from Zimbabwe was examined. PCR was used for the detection of both CPS types and the surface-anchored and strain-variable proteins C␣, C␤, Alp1, Alp2, Alp3, R4/Rib, and Alp4. The R3 protein was detected by an antibody-based method using monoclonal anti-R3 antibody in dot blotting. The CPS types detected, Ia (15.7% of strains), Ib (11.6%), II (8.3%), III (38.8%), V (24.0%), and nontypeable (1.7%), were essentially as expected on the basis of data from Western countries. The type V strains showed distinctive features with respect to protein markers in that Alp3 was detected in only 6.9% of the isolates while R3 occurred in 75.9% and R4/Rib occurred in 37.9% of the isolates. R3 occurred nearly always in combination with one of the alpha-like (Alp) proteins, and it was the third most common of the proteins studied. These results show that type V GBS strains from Zimbabwe differed from type V strains from other geographical areas and also emphasize the importance of the R3 protein in GBS serotyping and its potential importance in the immunobiology of GBS, including a potential role in a future GBS vaccine.

BackgroundTransfusion Transmissible Infections (TTIs) such as Human Immunodeficiency Virus (HIV), syphilis, hepatitis B virus (HBV) and hepatitis C virus (HCV) are infections which are common in some communities in Southern Africa. It is important to screen blood donations for these infections.MethodsThis is a retrospective study which involved reviewing of previous blood donation records for the year 2012 in Namibia. The records were analyzed to determine the prevalence of HIV, syphilis, Hepatitis B and C among blood donations with regard to gender, age and geographical region of the donors.ResultsThe findings indicated a significantly low prevalence of HIV, syphilis, HBsAg and anti-Hepatitis C among the blood donations. A low infection rate of 1.3% by any of the four tested TTIs was found among the blood donations given by the donor population in Namibia in 2012.ConclusionThe blood donations given by the donor population in Namibia has a low infection rate with the HIV, syphilis, HBsAg and anti-HCV. A strict screening regime must continue to be used as the infections are still present albeit in small numbers.

GBS colonization was common among pregnant women in Zimbabwe. Dwelling in a rural area was significantly associated with GBS colonization while other risk factors were not. Early GBS colonization had a low predictive value for colonization at delivery and colonization was not associated with adverse perinatal outcome.

Group B streptococci (GBS) express a variety of surface-exposed and strain-variable proteins which function as phenotypic markers and as antigens which are able to induce protective immunity in experimental settings. Among these proteins, the chimeric and immunologically cross-reacting alpha-like proteins are particularly important. Another protein, R3, which has been less well studied, occurred at a frequency of 21.5% in GBS from Zimbabwe and, notably, occurred in serotype V strains at a frequency of 75.9%. Working with rabbit antiserum raised against the R3 reference strain ATCC 49447 (strain 10/84; serotype V/R3) to detect the expression of the R3 protein, we recorded findings which suggested that strain 10/84 expressed a strain-variable protein antigen, in addition to R3. The antigen was detected by various enzyme-linked immunosorbent assay-based tests by using acid extract antigens or GBS whole-cell coats and by whole-cell-based Western blotting. We named the putative novel antigen the Z antigen. The Z antigen was a high-molecular-mass antigen that was susceptible to degradation by pepsin and trypsin but that was resistant to m-periodate oxidation and failed to show immunological cross-reactivity with any of a variety of other GBS protein antigens. The Z antigen was expressed by 33/121 (27.2%) of strains of a Zimbabwean GBS strain collection and by 64.2% and 72.4% of the type Ib and type V strains, respectively, and was occasionally expressed by GBS of other capsular serotypes. Thus, the putative novel GBS protein named Z showed distinct capsular antigen associations and presented as an important phenotypic marker in GBS from Zimbabwe. It may be an important antigen in GBS from larger areas of southern Africa. Its prevalence in GBS from Western countries is not known.Streptococcus agalactiae (the group B streptococcus [GBS]) possesses genotypic and phenotypic markers which are important in epidemiological settings. Among the established phenotypic markers, the capsular polysaccharides (CPSs) Ia, Ib, and II through IX play prominent roles in the classification of GBS, in the pathogenesis of GBS disease, and as targets of protective antibodies (15). A variety of surface-anchored and strain-variable proteins are also important GBS markers. These proteins make it possible to define GBS serosubtypes within each CPS type by using antibody-based or gene-based methods for subtyping (6, 11 19, 22). These proteins include Cß and the alpha-like proteins (Alps) C␣, Alp1 (formerly epsilon), Alp2 and Alp3 (formerly probably R1), and Rib (another designation for the R4 protein) (28). The Alps are characterized, among other ways, by a repeat-containing region which has a causal relation to the ladder-like patterns formed by these proteins on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and Western blotting. The Alps possess chimeric sequences, show variable immunological crossreactivities, and induce increased resistance to GBS infections in experimental models (1,13,15,18,30). For this reason, th...

The common capsular types found in this study are Ia, III, and II. The most common protein genes identified were rib and bca, and the distribution of the surface protein genes among the isolates of different capsular types showed similar trends to the distribution reported from previous studies.

Background During pregnancy, the vaginal microbiota is relatively stable. However, African women have more diverse vaginal microbiota than their European counterparts, in addition to high human immunodeficiency virus (HIV) prevalence and risk of adverse birth outcomes. Although HIV is associated with alterations in vaginal microbiota and inflammation in nonpregnant women, these relationships are underexplored in pregnant women. Methods In this study, we characterize the vaginal microbiota and immune factors in pregnant African women who were HIV-uninfected (n = 314) versus HIV-infected (n = 42). Mucosal samples were collected once at the enrollment visit (between 15 and 35 weeks of gestation) and women were followed until delivery. Results Vaginal microbial communities of pregnant women with HIV were significantly more diverse than women without HIV (P = .004), with community structure also differing by HIV status (P = .002, R2 = 0.02). Human immunodeficiency virus infection was also associated with increased risk of preterm birth (PTB) (31% versus 15.3%; P = .066). In a multivariate analysis, HIV infection was independently associated with diverse vaginal community state type (CST)-IVA (P = .005) and CST-IVB (P = .018) as well as PTB (P = .049). No association between HIV status and cytokine concentrations was found. Conclusions Longitudinal studies with accurate gestational age assessment would be important to confirm these relationships.

The results are of importance in relation to regional variations of GBS phenotypes and genotypes and thus, of importance in planning and research in the context of future vaccine formulations.