Does cotrimoxazole prophylaxis in HIV patients increase the drug resistance of pneumococci? A comparative cross-sectional study in southern Ethiopia.

BackgroundInfections caused by antibiotic-resistant bacteria results in high rates of morbidity and mortality. Although the prolonged cotrimoxazole (CTX) prophylaxis is arguably associated with the risk of increasing drug resistance in the common pathogens, information regarding its impact on Streptococci pneumoniae / pneumococcus is very limited.ObjectiveThis study was conducted to investigate the effect of cotrimoxazole prophylaxis on nasopharyngeal colonization rate and antimicrobial resistance using Streptococci pneumoniae (pneumococcus) as an indicator organism among HIV patients in Arba Minch, Ethiopia.Materials and methodsA comparative cross-sectional study was designed and conducted among HIV patients attending the Anti-Retroviral Treatment (ART) clinic of Arba Minch General Hospital (AMGH) from April 01 to August 31, 2018. A total of 252 participants were systematically selected and clustered into two study groups based on their CTX prophylaxis status, one taking CTX prophylaxis, and the second one, the control group (without prophylaxis). A structured questionnaire was used to collect socio-demographic and clinical data from patients. A nasopharyngeal swab was collected and cultured for pneumococcal isolation and identification in accordance with standard microbiological techniques. An antibiotics sensitivity test was performed according to the CLSI guidelines. Data were analyzed using the Statistical package for social science (SPSS) version 20. The primary outcome was determined using logistic regression analysis.ResultsOf the 252 enrolled HIV patients (mean age (37.38± 9.03 years), 144 (57.14%) were males. The overall, nasopharyngeal colonization rate of S. pneumoniae was 13.5% (95% CI: 8.4-15.6). Asymptomatic pneumococcal carriage rates among patients on CTX prophylaxis and the control group were 16.3%, and 10.3% respectively (p-value = 0.03). Regarding the risk factors analyzed, CTX prophylaxis (AOR: 2.2; 95% CI: 1.05-4.9) and gender (AOR: 2.5; 95% CI: 1.09-5.93) were significantly associated with pneumococcal colonization, showing a male preponderance. Cotrimoxazole-resistant pneumococci were 85.7% vs. 47.4% in the prophylaxis group and the control group respectively and it was statistically significant (AOR: 6.7; 95% CI: 1.3-36). Percentages of multi-drug resistant isolates in these two groups were 38.09 and 15.38 respectively (p-value = 0.04). Among the CTX resistant pneumococci isolates, 85% were also found to be co-resistant towards penicillin and was statistically significant.ConclusionThe percentage prevalence of nasopharyngeal pneumococci colonization was higher in patients taking CTX prophylaxis. It was noted that CTX prophylaxis eventually results in the selection of cotrimoxazole resistance and multi-drug resistance in pneumococci. There is evidence of existing cross-resistance between cotrimoxazole and penicillin antibiotics. Therefore, CTX prophylaxis must be administered judiciously. Surveillance for antimicrobial susceptibility is warranted where the prophylaxis is common

Whole genome sequencing reveals within-host genetic changes in paired meningococcal carriage isolates from Ethiopia

Background: Meningococcal colonization is a prerequisite for transmission and disease, but the bacterium only very infrequently causes disease while asymptomatic carriage is common. Carriage is highly dynamic, showing a great variety across time and space within and across populations, but also within individuals. The understanding of genetic changes in the meningococcus during carriage, when the bacteria resides in its natural niche, is important for understanding not only the carriage state, but the dynamics of the entire meningococcal population. Results: Paired meningococcal isolates, obtained from 50 asymptomatic carriers about 2 months apart were analyzed with whole genome sequencing (WGS). Phylogenetic analysis revealed that most paired isolates from the same individual were closely related, and the average and median number of allelic differences between paired isolates defined as the same strain was 35. About twice as many differences were seen between isolates from different individuals within the same sequence type (ST). In 8%, different strains were detected at different time points. A difference in ST was observed in 6%, including an individual who was found to carry three different STs over the course of 9 weeks. One individual carried different strains from the same ST. In total, 566 of 1605 cgMLST genes had undergone within-host genetic changes in one or more pairs. The most frequently changed cgMLST gene was relA that was changed in 47% of pairs. Across the whole genome, pilE, differed mostly, in 85% of the pairs. The most frequent mechanisms of genetic difference between paired isolates were phase variation and recombination, including gene conversion. Different STs showed variation with regard to which genes that were most frequently changed, mostly due to absence/presence of phase variation. Conclusions: This study revealed within-host genetic differences in meningococcal isolates during short-term asymptomatic carriage. The most frequently changed genes were genes belonging to the pilin family, the restriction/modification system, opacity proteins and genes involved in glycosylation. Higher resolution genome-wide sequence typing is necessary to resolve the diversity of isolates and reveals genetic differences not discovered by traditional typing schemes, and would be the preferred choice of technology

Prevalence and epidemiology of meningococcal carriage in Southern Ethiopia prior to implementation of MenAfriVac, a conjugate vaccine

Abstract Background Neisseria meningitidis colonizes humans and transmits mainly by asymptomatic carriage. We sought to determine the prevalence and epidemiology of meningococcal carriage in Ethiopia prior to the introduction of MenAfriVac, a serogroup A meningococcal conjugate vaccine. Methods A cross-sectional meningococcal carriage study was conducted in Arba Minch, southern Ethiopia. A total of 7479 oropharyngeal samples were collected from 1 to 29 year old volunteers, between March and October, 2014. The swabs were cultured for N. meningitidis and Neisseria lactamica in Ethiopia. N. meningitidis isolates were confirmed and characterized by their serogroup, sequence type (ST) and PorA:FetA profile in Norway. Results Overall carriage prevalence was 6.6 %. There was no significant difference in overall carriage between male (6.7 %) and female (6.4 %) participants. Highest carriage prevalence (10.9 %) for females was found in the 15–19 years of age, while prevalence among males was highest (11.3 %) in the 20–24 age group. Non-groupable isolates dominated (76.4 %), followed by serogroups X (14.0 %) and W (5.9 %) isolates. No serogroup A was found. Most non-groupable isolates were ST-192. Serogroup W isolates were assigned to the ST-11 clonal complex, and serogroup X isolates to the ST-181 and ST-41/44 clonal complexes. Overall carriage prevalence of N. lactamica was 28.1 %. Carriage of N. meningitidis and N. lactamica varied depending on age and geographic area, but there was no association between carriage of the two species. Conclusions Epidemic strains of serogroups W and X were circulating in this area of Ethiopia. As no serogroup A was found among the carriage isolates the immediate impact of mass-vaccination with MenAfriVac on transmission of N. meningitidis in this population is expected to be marginal

Salivary and serum antibody response against Neisseria meningitidis after vaccination with conjugate polysaccharide vaccines in Ethiopian volunteers

Meningococcal conjugate vaccines induce serum antibodies crucial for protection against invasive disease. Salivary antibodies are believed to be important for hindering meningococcal acquisition and/or clearance of established carriage. In this study, we measured salivary IgA and IgG antibodies induced by vaccination with a monovalent serogroup A conjugate vaccine or a tetravalent A, C, W and Y conjugate vaccine, in comparison with antibody levels in serum. Saliva and serum samples from Ethiopian volunteers (1–29 years) collected before and eight times on a weekly basis after receiving the serogroup A conjugate vaccine, the tetravalent serogroup A, C, W and Y conjugate vaccine, or no vaccine (control group), were analysed using a multiplex microsphere immunoassay for antibody detection. Serogroup-specific IgG antibody levels in saliva increased significantly after vaccination with both vaccines. The monovalent serogroup A vaccine also induced an increase in salivary IgA antibodies. A strong correlation between serogroup-specific IgG antibodies in saliva and serum, and a somewhat lower correlation for IgA, was observed for all serogroups. There was also a strong correlation between specific secretory IgA and IgA antibodies in saliva for all serogroups. Meningococcal conjugate vaccines are able to elicit salivary antibodies against serogroup A, C, W and Y correlating with antibody levels in serum. The strong correlation between saliva and serum antibody levels indicates that saliva may be used as a surrogate of systemic antibody responses

Additional file 2: Figure S1. of Whole genome sequencing reveals within-host genetic changes in paired meningococcal carriage isolates from Ethiopia

Bayesian analysis of population structure (BAPS) clusters of paired meningococcal carriage isolates per sequence type. Neighbor-net splits trees of allelic differences in N. meningitidis core genome MLST genes (N. meningitidis cgMLST v1.0, available at pubMLST.org). Panel A, B, C and D show sequence types (ST) ST-11, ST-53, ST-192 and ST-2880, respectively. BAPS clusters are highlighted by circles and numbered sequentially. Paired isolates from the same individual that have been assigned to different BAPS clusters are underlined and connected with dashed lines. (ZIP 56 kb