Evaluation of antigen-based rapid detection test for the diagnosis of SARS CoV-2 in low-income countries.

BACKGROUND: In the context of the Covid-19 pandemic and following the increasing number of suspicious Covid-19 cases in Madagascar, Malagasy laboratories are overflowed mainly due to lack of human resource and available material restriction. The development and validation of rapid and easy-to-perform diagnostic methods are worth of interest and high priority. The aim of this prospective study was to evaluate the performances of a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to Reverse transcription polymerase chain reaction (RT-PCR). METHODS: The fluorescence immunochromatographic SARS-CoV-2 antigen test StandardTM Q COVID-19 Ag Test (SD Biosensor Republic Korea) was evaluated in samples derived from patients who were examined for disease categories. Diagnostic accuracy was determined in comparison to SARS-CoV-2 RT-PCR considered as gold standard. RESULTS: A total of 200 samples were included; 94 were RT-PCR positive. Median patients' age was 38.36 years, 63.5 % were male. Overall sensitivity and specificity of the Standard TM Q COVID-19 Ag (SD Biosensor® Republic Korea) were 62.66 % and 100 %, the sensitivity was significantly higher (100 %) in samples with high viral loads (Ct<29). CONCLUSIONS: This antigen-based immunofluorescence RDT could be the potential to become an important tool for the early diagnosis of SARS-CoV-2 particularly in situations with limited access to molecular methods particularly in rural area of Madagascar.

Corynebacterium diphtheriae Infection in Mahajanga, Madagascar: First Case Report.

Diphtheria is an infection that has been unreported for more than two decades in Mahajanga. A child, aged 4, presented with a pseudomembranous pharyngitis was associated with a dysphagia. He was from a rural municipality of Ambato Boeny at Mahajanga province and was admitted to the Pediatric Unit of the University Hospital Center. The child was not immunized against diphtheria. A throat swab was performed and cultured, from which Corynebacterium diphtheriae was identified. The strain, of biovar Mitis, was confirmed as diphtheria toxin (DT)-gene positive and produced DT (Elek test). Unfortunately, the child developed cardiac and neurological complications and died of respiratory and heart failure.

Dermatophyte infection caused by Nannizzia gypsea: A rare case report from Madagascar.

We report a rare case of dermatophyte infection of the glabrous skin (Tinea corporis) caused by Nannizzia gypsea (formerly Microsporum gypseum). A 22-year-old Malagasy female who reported close contact reportedly with cats, presented a single round lesion with a peripheral, active, squamous and pruriginous inflammatory bead. Morphologic species identification was confirmed by sequencing the internal transcribed spacer (ITS) region of the genome. Specific treatment with oral loratadine and topical miconazole cream was effective.

Evaluation of methicillin-resistant Staphylococcus aureus nasal carriage in Malagasy pig and poultry non-industrial farmers.

INTRODUCTION: The laboratory of Training and Research in Medical Biology of Madagascar conducted a cross-sectional study to estimate the rate of S. aureus nasal carriage of pig and poultry Malagasy farmers. METHODOLOGY: Pig and poultry farmers from capital town of Madagascar were selected for nasal swabs collection with information on potential risk factors for S. aureus colonization, including animal exposure. RESULTS: Nasal swabs from 180 farmers (M/F sex ratio: 0.74), enabled isolation after culture and biochemical identification, 69 (38.33%) S. aureus strains among which 45 (25%) were methicillin-resistant (MRSA). Risk factors analysis revealed that farming duration, number of animals, direct contact with poultry, and frequent contact with manure increased risk of S. aureus and MRSA nasal carriage. Likewise, farm practices that imply close contact with pigs such as food distribution and pigsty washing increased risk of S. aureus and MRSA nasal carriage among pig farmers. Among MRSA isolates, resistance rate to other antibiotics was similar to that of MRSA isolates from the non-farmer Malagasy population. However, gentamycin resistance was noticeably higher (32.5% versus 4.44%). CONCLUSIONS: This study shows a high rate of S. aureus and MRSA nasal carriage with high rate of multidrug resistance among healthy people frequently in contact with animals. A strategic policy against the spread of multidrug-resistant strains is desirable in farms and veterinary areas.

[Seroprevalence of cysticercosis and associated risk factors in a group of patients examined at the Regional Referral Hospital in Antsirabe]. / Séroprévalence de la cysticercose et facteurs de risque associés chez un groupe de patients vus au Centre Hospitalier Régional de Référence d'Antsirabe, Madagascar.

INTRODUCTION: In Madagascar, cysticercosis, a disease caused by Taenia Solium's larval form, is a public health problem. In 2003, the seroprevalence of cysticercosis ranged between 7% and 21% with a higher rate in the central regions of the island. However, epidemiological data on human cysticercosis have been limited over the last dozen years. The objective of our study aimed to determine the seroprevalence of cysticercosis Western blot as well as its associated risk factors in patients from the region of Vakinankaratra with clinical suspicion. METHODS: We conducted a cross-sectional, descriptive study at the Regional Referral Hospital in Antsirabe over a period of 6 months. All the patients included in the study answered a clinic questionnaire collecting their socio-demographic and cultural features as well as their dietary habits and their clinical symptoms. RESULTS: The seroprevalence of cysticercosis in the study population was 14.8% (35/237). These rates did not differ significantly according to sex, age, pork consumption or meat preparation (p > 0.05). However, a significant difference (p < 0.05) was observed among patients with subcutaneous nodules or positive for cysticercosis. CONCLUSION: In our study, the high index of exposure to Taenia solium justifies the strengthening of control and prevention measures already set up in our country.

Pseudomonas aeruginosa Biofilm Formation and Persistence, along with the Production of Quorum Sensing-Dependent Virulence Factors, Are Disrupted by a Triterpenoid Coumarate Ester Isolated from Dalbergia trichocarpa, a Tropical Legume.

Recently, extracts of Dalbergia trichocarpa bark have been shown to disrupt P. aeruginosa PAO1 quorum sensing (QS) mechanisms, which are key regulators of virulence factor expression and implicated in biofilm formation. One of the active compounds has been isolated and identified as oleanolic aldehyde coumarate (OALC), a novel bioactive compound that inhibits the formation of P. aeruginosa PAO1 biofilm and its maintenance as well as the expression of the las and rhl QS systems. Consequently, the production of QS-controlled virulence factors including, rhamnolipids, pyocyanin, elastase and extracellular polysaccharides as well as twitching and swarming motilities is reduced. Native acylhomoserine lactones (AHLs) production is inhibited by OALC but exogenous supply of AHLs does not restore the production of virulence factors by OALC-treated cultures, indicating that OALC exerts its effect beyond AHLs synthesis in the QS pathways. Further experiments provided a significant inhibition of the global virulence factor activator gacA by OALC. OALC disorganizes established biofilm structure and improves the bactericidal activity of tobramycin against biofilm-encapsulated PAO1 cells. Finally, a significant reduction of Caenorhabditis elegans paralysis was recorded when the worms were infected with OALC-pre-treated P. aeruginosa. Taken together, these results show that triterpenoid coumarate esters are suitable chemical backbones to target P. aeruginosa virulence mechanisms.

Current practice about the evaluation of antibody to streptolysin O (ASO) levels by physicians working in Antananarivo, Madagascar.

INTRODUCTION: The diagnosis of post streptococcal diseases is usually confirmed by immunological tests. Only the antistreptolysin O is usually prescribed by physician. This study aimed to describe the current practice of these requests in Antananarivo. METHODS: It was a retrospective and descriptive study conducted at the Para clinic Unit of Immunology at the University Center Hospital of Antananarivo. We analyzed all requests during seven years, from January 2003 to December 2009. We looked at age, gender, and clinical symptoms which led to the request and the result for each request. RESULTS: We retained 4143 requests for antistreptolysin O titration in our study. The mean age of the study participants was 32.9 years with 18.3% of participants being less than 15 years old. The main symptoms leading to the request of this analysis were rheumatologic (41%), followed by neurological (13.9%) and cardiologic symptoms (8.5%) and 19.4% were prescribed for various symptoms. Only 15% of all requests had a value more than 200 U/ml. CONCLUSION: Our study found that in most of requests, ASO titre levels were not significant.

Evaluation of methicillin-resistant Staphylococcus aureus nasal carriage in Malagasy patients.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of infections. It is well recognized that nasal carriage of S. aureus represents a potent and increasingly prevalent risk factor for subsequent S. aureus infection. However, in Madagascar no data exist concerning this nasal carriage of S. aureus. METHODOLOGY: Nasal swabs from 304 different patients attending the Laboratory of Training and Research in Medical Biology of Madagascar were cultured for methicillin sensitive (MSSA) and MRSA. RESULTS: One hundred and sixteen patients had S. aureus in their noses (38.16 ± 5.46%) of whom 45 (14.80 ± 3.99%) had MRSA.  A risk factor for MSSA nasal carriage included a history of hospitalization when antibiotics were administered (odds ratio [OR] 2.25, 1.09 - 4.64). Among MRSA nasal isolates, high rate of resistance to other antibiotics was observed, particularly for trimethoprim-sulfamethoxazole (68.89%), erythromycin (66.67%) and ofloxacin (53.33%). CONCLUSIONS: Our data showed a high rate of MRSA nasal carriage and a high rate of multidrug resistance. A strategic policy against the spread of multidrug resistant strains is desirable.

Endemic malagasy Dalbergia species inhibit quorum sensing in Pseudomonas aeruginosa PAO1.

Various species of the plant genus Dalbergia are traditionally used as medicine for sundry ailments and some of them have been shown recently to quench the virulence of Gram-positive and Gram-negative bacteria. Cell-to-cell communication mechanisms, quorum sensing (QS) in particular, are key regulators of virulence in many pathogenic bacteria. Screening n-hexane extracts of leaves, roots and bark of endemic Malagasy Dalbergia species for their capacity to antagonize QS mechanisms in Pseudomonas aeruginosa PAO1 showed that many reduced the expression of the QS-regulated genes lasB and rhlA. However, only the extract of Dalbergia trichocarpa bark (DTB) showed a significant reduction of QS gene expression without any effect on the aceA gene encoding a QS-independent isocitrate lyase. Further characterization of DTB impact on QS revealed that the QS systems las and rhl are inhibited and that swarming, twitching, biofilm formation and the production of pyocyanin, elastase and proteases are also hampered in the presence of the DTB extract. Importantly, compared with the known QS inhibitor naringenin, the DTB extract showed a stronger negative effect on twitching, biofilm formation and tobramycin resistance. Preliminary structural characterization of these potent biofilm disrupters suggests that they belong to the phytosterols. The strong inhibition of motility and biofilm formation suggests that the DTB extract contains agents disrupting biofilm architecture, which is an important observation in the context of the design of new drugs targeting biofilm-encapsulated pathogens.

Randomised controlled trial of alternative male and female condom promotion strategies targeting sex workers in Madagascar.

OBJECTIVES: To assess whether individual clinic-based counselling as a supplement to peer education for male and female condom promotion leads to greater use of protection and lower STI prevalence among sex workers in Madagascar already exposed to intensive male condom promotion. METHODS: In two public dispensaries in Madagascar, a total of 901 sex workers were randomly allocated between two alternative male and female condom promotion INTERVENTIONS: peer education only, or peer education supplemented with individual clinic-based counselling. Participants were followed for 12 months. Every 2 months they made clinic visits, where they were interviewed on condom use. Peer educators counselled all participants on condom use as they accompanied their assigned participants to study visits. Participants assigned to receive the supplemental intervention were counselled by a trained clinician following study interviews. Participants were tested and treated for chlamydia, gonorrhoea and trichomoniasis every 6 months. We used logistic regression to assess whether the more intensive intervention was associated with reduced STI prevalence. Use of protection with clients and non-paying partners was assessed by study arm, site, and visit. RESULTS: There was no statistically significant association between study arm and aggregated STI prevalence. No substantial differences in levels of reported protection were noted between study groups. CONCLUSIONS: This study found little evidence for gains from more thorough clinical counselling on male and female condom use. These findings suggest that less clinically intensive interventions such as peer education could be suitable for male and female condom promotion in populations already exposed to barrier method promotion.

Increased risk of chlamydial and gonococcal infection in adolescent sex workers in Madagascar.

GOAL: To examine and compare young sex workers' risk of acquisition of sexually transmitted infections (STIs) with the risk among their older counterparts. OBJECTIVE: To evaluate the effect of young age--16-19 years vs. 20 years and older--on risk of incident infection with Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT). STUDY DESIGN: A randomized controlled trial of 1,000 sex workers in Madagascar was conducted. STI testing was conducted at baseline, 6, 12, and 18 months. RESULTS: About 13% of the cohort (n = 134) was composed of young women aged 16-19 years. STI incidence rates in this group over the 18-month study period were high: 51.9/100 woman-years (WY) for GC and 47.4/100 WY for CT compared to 27.4/100 WY and 19.1/100 WY for sex workers over age 20, respectively. In multivariable models, young sex workers were at significantly higher STI risk compared with their older peers: The adjusted risk ratio (aRR) for GC comparing younger to older women was 1.50 (95% confidence interval (CI): 1.20, 1.88); for CT, the aRR was 1.72 (95% CI: 1.35, 2.19) and for GC or CT combined, the aRR was 1.42 (95% CI: 1.22, 1.66). CONCLUSIONS: This exploratory analysis suggests that additional research is warranted to identify effective and acceptable prevention strategies that benefit young women, and interventions already proven effective among adolescents should be given high priority for scale-up.

Socio-demographic and behavioural factors associated with high incidence of sexually transmitted infections in female sex workers in Madagascar following presumptive therapy.

BACKGROUND: Too little is known about the many women who generate income in Madagascar by trading sex. METHODS: Clinical and laboratory exams were offered to 493 non-care seeking female sex workers (SWs) in Antananarivo and 493 in Tamatave. SWs were recruited by peers in their community; they were interviewed, counselled and treated for sexually transmitted infections (STIs) at recruitment and re-evaluated 2 months later. RESULTS: One hundred and eighty six (38%) of the SWs in Antananarivo and 113 (23%) in Tamatave did not complete primary school (P < 0.0001). The incidence rates per person per month in Antananarivo and Tamatave, respectively, were 0.09 and 0.08 for gonorrhoea; 0.05 and 0.03 for chlamydia; 0.24 and 0.15 for trichomoniasis; 0.07 and 0.05 for syphilis. At follow-up, consistent condom use with clients was reported by 56 (12%) SWs in Antananarivo and 137 (29%) in Tamatave (P < 0.0001); 320 (70%) SWs in Antananarivo and 11 (2%) in Tamatave reported sex with a non-paying partner in the past month (P < 0.0001). In Antananarivo, 422 (92%) of the SWs thought they were at no or low risk of having an STI compared to 100 (21%) in Tamatave (P = 0.02). At follow-up, 277 (61%) SWs reported no birth control for their last sex act in Antananarivo, compared to 26 (5%) in Tamatave (P < 0.0001). Socio-demographic and behavioural risk factors for incident gonorrhoea, chlamydia and trichomoniasis varied by city. CONCLUSIONS: Strategies to address the needs of women who trade sex should include educational and economic opportunities; should tackle male partners of SWs; promote dual protection against unintended pregnancy and STIs, while taking into account local socio-demographic and behavioural characteristics.

Genetic typing of the porin protein of Neisseria gonorrhoeae from clinical noncultured samples for strain characterization and identification of mixed gonococcal infections.

Molecular methods that characterize the Neisseria gonorrhoeae porin protein Por are needed to study gonococcal pathogenesis in the natural host and to classify strains from direct clinical samples used with nucleic acid amplification-based tests. We have defined the capabilities of por variable region (VR) typing and determined suitable conditions to apply the method to direct clinical specimens. Nested PCR from spiked urine samples detected 1 to 10 copies of template DNA; freezing spiked whole urine greatly reduced the ability to amplify porB. In a laboratory model of mixed gonococcal infections, the por type of one strain could be determined in the presence of a 100-fold excess of another. por VR typing was used to examine clinical samples from women enrolled in studies conducted in Baltimore, Md., and Madagascar. por type was determined from 100% of paired cervical swab and wick samples from 20 culture-positive women from Baltimore; results for eight individuals (40%) suggested infection with more than one strain. In frozen urine samples from Madagascar, porB was amplified and typed from 60 of 126 samples from ligase chain reaction (LCR)-positive women and 3 samples from LCR-negative women. The por VR types of 13 samples (21%) suggested the presence of more than one gonococcal strain. Five por types, identified in >45% of women with typed samples, were common to both geographic areas. Molecular typing is an important adjunct to nucleic acid amplification-based diagnostics. Methods that utilize direct clinical samples and can identify mixed infections may contribute significantly to studies of host immunity, gonococcal epidemiology, and pathogenesis.