Salmonella enterica serovars Typhimurium and Enteritidis causing mixed infections in febrile children in Mozambique

Background and purpose: Invasive nontyphoidal salmonellosis, mostly caused by serovars Typhimurium and Enteritidis of Salmonella enterica, has emerged as a major public health problem in sub-Saharan Africa. The aim of this study was the clinical and microbiological characterization of nontyphoidal salmonellosis episodes affecting febrile children in Mozambique. Patients and methods: The clinical records of the patients were evaluated, and S. enterica isolates were characterized with regard to serovar, phage type, antimicrobial resistance (phenotype/responsible genes), plasmid content, pulsed-field gel electrophoresis, and multilocus sequence typing. Results: Fifteen S. Typhimurium and 21 S. Enteritidis isolates were recovered from blood samples of 25 children, the majority with underlying risk factors. With regard to phage typing, most isolates were either untypeable or reacted but did not conform, revealing that a number of previously unrecognized patterns are circulating in Mozambique. Most isolates were multidrug-resistant, with nearly all of the responsible genes located on derivatives of serovar-specific virulence plasmids. ST313 and ST11 were the predominant sequence types associated with S. Typhimurium and S. Enteritidis, respectively, and the uncommon ST1479 was also detected in S. Enteritidis. A distinct XbaI fragment of ~350 kb was associated with pulsed-field gel electrophoresis patterns of multidrug-resistant isolates of S. Enteritidis. Nearly half of the children were coinfected with both serovars, a fact expected to aggravate the disease and hamper the treatment. However, particularly poor outcomes were not observed for the coinfected patients. Conclusion: Mixed Salmonella infections could frequently occur in febrile children in Mozambique. Additional studies are required to determine their actual impact and consequences, not only in this country, but also in other African countries

Do Xpert MTB/RIF Cycle Threshold Values Provide Information about Patient Delays for Tuberculosis Diagnosis?

INTRODUCTION: Early diagnosis and initiation to appropriate treatment is vital for tuberculosis (TB) control. The XpertMTB/RIF (Xpert) assay offers rapid TB diagnosis and quantitative estimation of bacterial burden through Cycle threshold (Ct) values. We assessed whether the Xpert Ct value is associated with delayed TB diagnosis as a potential monitoring tool for TB control programme performance. MATERIALS AND METHODS: This analysis was nested in a prospective study under the routine TB surveillance procedures of the National TB Control Program in Manhica district, Maputo province, Mozambique. Presumptive TB patients were tested using smear microscopy and Xpert. We explored the association between Xpert Ct values and self-reported delay of Xpert-positive TB patients as recorded at the time of diagnosis enrolment. Patients with >60 days of TB symptoms were considered to have long delays. RESULTS: Of 1,483 presumptive TB cases, 580 were diagnosed as TB of whom 505 (87.0%) were due to pulmonary TB and 302 (94.1%) were Xpert positive. Ct values (range, 9.7-46.4) showed a multimodal distribution. The median (IQR) delay was 30 (30-45) days. Ct values showed no correlation with delay (R2 = 0.001, p = 0.621), nor any association with long delays: adjusted odds ratios (AOR) (95% confidence interval [CI]) comparing to >28 cycles 0.99 (0.50-1.96; p = 0.987) for 23-28 cycles, 0.93 (0.50-1.74; p = 0.828) for 16-22 cycles; and 1.05 (0.47-2.36; p = 0.897) for <16 cycles. Being HIV-negative (AOR [95% CI]), 2.05 (1.19-3.51, p = 0.009) and rural residence 1.74 (1.08-2.81, p = 0.023), were independent predictors of long delays. CONCLUSION: Xpert Ct values were not associated with patient delay for TB diagnosis and cannot be used as an indicator of TB control program performance

Structural Insight into Host Recognition by Aggregative Adherence Fimbriae of Enteroaggregative Escherichia coli

AVZ is supported by the Finnish Academy (grant 273075; http://sciencenordic.com/partner/academy-finland). The EACEA (http://eacea.ec.europa.eu) supports NP for an Erasmus Mundus scholarship. SM is supported by the Wellcome Trust (Senior Investigator Award 100280, Programme grant 079819; equipment grant 085464; http://www.wellcome.ac.uk)) and the Leverhulme Trust (RPG-2012-559; http://www.leverhulme.ac.uk). JPN and AAB are supported by a US Public Health Service grant (AI-033096; www.usphs.gov). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Characterisation of extended-spectrum b-lactamases among Klebsiella pneumoniae isolates causing bacteraemia and urinary tract infection in Mozambique

The aim of this study was to determine the prevalence of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolated from urinary tract and bloodstream infections in a rural hospital in Manhiça, Mozambique. ESBLs were investigated among ceftriaxone-non-susceptible K. pneumoniae clinical isolates recovered between 2004 and 2009. Characterisation of blaCTX-M, blaSHV, blaOXA and blaTEM genes was performed by PCR and sequencing. Epidemiological relationships were established by phylogenetic analysis, repetitive extragenic palindromic PCR (REP-PCR), pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST), whilst plasmid transferability was evaluated by conjugation. In addition, the presence of class 1 and 2 integrons was studied. A total of 19 K. pneumoniae were analysed. The blaCTX-M-15 gene was found in all strains. Other ESBL genes were found concomitantly, including blaSHV-5, blaSHV-2, blaSHV-2A, blaSHV-12 and blaSHV-38. In addition, other β-lactamases such as blaTEM-1 and blaOXA-30 were also detected. REP-PCR identified 15 different epidemiological profiles. MLST analysis also showed great variability of sequence types. The blaCTX-M-15 gene showed a high transfer capacity. The presence of class 1 integrons was high. High levels of multidrug resistance were also found. In conclusion, these data show the dominance of the CTX-M-type ESBL, particularly CTX-M-15, supporting its worldwide dissemination, including in areas with limited access to third-generation cephalosporins. This finding is a matter of concern for clinical management as third-generation cephalosporins are an alternative for treating severe cases of multidrug-resistant infections in this community

Characterization of Vaginal Escherichia coli Isolated from Pregnant Women in Two Different African Sites

The relevance of vaginal colonization of pregnant women by Escherichia coli is poorly understood, despite these strains sharing a similar virulence profile with other extraintestinal pathogenic E. coli producing severe obstetric and neonatal infections. We characterized the epidemiology, antimicrobial susceptibility and virulence profiles of 84 vaginal E. coli isolates from pregnant women from Rabat (Morocco) and Manhica (Mozambique), two very distinct epidemiological settings. Low levels of antimicrobial resistance were observed to all drugs tested, except for trimethoprim-sulfamethoxazole in Manhica, where this drug is extensively used as prophylaxis for opportunistic HIV infections. The most prevalent virulence factors were related to iron acquisition systems. Phylogroup A was the most common in Rabat, while phylogroups E and non-typeable were the most frequent in Manhica. Regardless of the apparently "low virulence" of these isolates, the frequency of infections is higher and the outcomes more devastating in constrained-resources conditions, especially among pregnant women and newborns

Burden of disease and circulating serotypes of rotavirus infection in sub-Saharan Africa: systematic review and meta-analysis.

Two new rotavirus vaccines have recently been licensed in many countries. However, their efficacy has only been shown against certain serotypes commonly circulating in Europe, North America, and Latin America, but thought to be globally important. To assess the potential impact of these vaccines in sub-Saharan Africa, where rotavirus mortality is high, knowledge of prevalent types is essential because an effective rotavirus vaccine is needed to protect against prevailing serotypes in the community. We did two systematic reviews and two meta-analyses of the most recent published data on the burden of rotavirus disease in children aged under 5 years and rotavirus serotypes circulating in countries in sub-Saharan Africa. Eligible studies were selected from PubMed/Medline, Cochrane Library, EmBase, LILACS, Academic Search Premier, Biological Abstracts, ISI Web of Science, and the African Index Medicus. Depending on the heterogeneity, DerSimonian-Laird random-effects or fixed-effects models were used for meta-analyses. Geographical variability in rotavirus burden within countries in sub-Saharan Africa is substantial, and most countries lack information on rotavirus epidemiology. We estimated that annual mortality for this region was 243.3 (95% CI 187.6-301.7) deaths per 100,000 under 5 years (ie, a total of 300,000 children die of rotavirus infection in this region each year). The most common G type detected was G1 (34.9%), followed by G2 (9.1%), and G3 (8.6%). The most common P types detected were P[8] (35.5%) and P[6] (27.5%). Accurate information should be collected from surveillance based on standardised methods in these countries to obtain comparable data on the burden of disease and the circulating strains to assess the potential impact of vaccine introduction

Cytoadhesion to gC1qR through Plasmodium falciparum Erythrocyte Membrane Protein 1 in Severe Malaria

Cytoadhesion of Plasmodium falciparum infected erythrocytes to gC1qR has been associated with severe malaria, but the parasite ligand involved is currently unknown. To assess if binding to gC1qR is mediated through the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family, we analyzed by static binding assays and qPCR the cytoadhesion and var gene transcriptional profile of 86 P. falciparum isolates from Mozambican children with severe and uncomplicated malaria, as well as of a P. falciparum 3D7 line selected for binding to gC1qR (Pf3D7gC1qR). Transcript levels of DC8 correlated positively with cytoadhesion to gC1qR (rho = 0.287, P = 0.007), were higher in isolates from children with severe anemia than with uncomplicated malaria, as well as in isolates from Europeans presenting a first episode of malaria (n = 21) than Mozambican adults (n = 25), and were associated with an increased IgG recognition of infected erythrocytes by flow cytometry. Pf3D7gC1qR overexpressed the DC8 type PFD0020c (5.3-fold transcript levels relative to Seryl-tRNA-synthetase gene) compared to the unselected line (0.001-fold). DBLbeta12 from PFD0020c bound to gC1qR in ELISA-based binding assays and polyclonal antibodies against this domain were able to inhibit binding to gC1qR of Pf3D7gC1qR and four Mozambican P. falciparum isolates by 50%. Our results show that DC8-type PfEMP1s mediate binding to gC1qR through conserved surface epitopes in DBLbeta12 domain which can be inhibited by strain-transcending functional antibodies. This study supports a key role for gC1qR in malaria-associated endovascular pathogenesis and suggests the feasibility of designing interventions against severe malaria targeting this specific interaction

Carriage prevalence of Salmonella enterica serotype Typhi in gallbladders of adult autopsy cases from Mozambique

INTRODUCTION: Typhoid fever is an important public health problem in many low-income countries where asymptomatic carriers play an important role in its dissemination. The bacterium causing typhoid fever can live in the gallstones of asymptomatic persons after the infection. These carriers are reservoirs of S. Typhi, are highly contagious, and spread the disease through the secretion of bacteria in feces and urine. The aim of this study was to determine the carrier rate in an area of Mozambique. METHODOLOGY: The presence of S. Typhi was analyzed in gallbladder samples obtained from 99 adult corpses (in-hospital deaths) from Mozambique by gold-standard culture and polymerase chain reaction (PCR). RESULTS: Only one sample was positive with the culture. However, nine additional samples were positive by PCR and confirmed by DNA sequencing. Thus, the prevalence of S. Typhi was 10.1% (10/99). CONCLUSIONS: We report a high prevalence of S. Typhi in gallbladders among adult autopsy cases from Mozambique

The role of Xpert MTB/RIF in diagnosing pulmonary tuberculosis in post-mortem tissues

The extent to which the Xpert MTB/RIF (Gene Xpert) contributes to tuberculosis (TB) diagnosis in samples other than sputum and cerebrospinal fluid remains uncertain. We aimed to assess the role of Xpert MTB/RIF for detecting M. tuberculosis in post-mortem tissues. We conducted a study among 30 complete diagnostic autopsies (CDA) performed at the Maputo Central Hospital (Mozambique). Lung tissues were screened for TB in all cases. In addition other tissues were tested when compatible lesions were identified in the histological exam. We used in-house real time PCR and LAMP assays to confirm the presence of M. tuberculosis DNA. The diagnosis of tuberculosis at death was established based on microbiological and histopathological results. Eight out of 30 cases (26.7%) were diagnosed of tuberculosis. Xpert had a sensitivity to detect TB in lung tissue of 87.5% (95% CI 47.3-99.7) and a specificity of 95.7% (95% CI: 78.1-99.9). In-house DNA amplification methods and Xpert showed 93.6% concordance for lung tissue and 100% concordance for brain and liver tissues. The final cause of death was attributable to tuberculosis in four cases. Xpert MTB/RIF may represent a valuable, easy-to perform technique for post-mortem TB diagnosis