Medical Microbiology & Diagnosis

Background: Pre-existing mucosal generated secretory IgA antibodies may prevent transmission of HIV. The present study aimed to characterize mucosal antibodies generated following topical vaccination with a novel mucosal adjuvant, angiotensin (1-7), in combination with a killed feline immunodeficiency virus (FIV) vaccine used as a model antigen.

Methods: Female outbred cats were vaccinated with Fel-O-Vax FIV vaccine agent combined with increasing concentrations of angiotensin (1-7) [A (1-7)] applied topically to oral, vaginal and rectal surfaces weekly for six weeks. Control animals received intramuscular vaccinations with the Fel-O-Vax FIV alone or with A (1-7). Mucosal secretions were evaluated for antibody responses against FIV-p24 antigen or HIV-gp120 antigen.

Results: Topical application of whole killed FIV virus with A (1-7) induced substantial secretory IgA (SIgA)-antigp120 antibodies in oral, vaginal and rectal secretions across a wide ranges of A (1-7) dose levels. Intramuscular vaccination of FIV antigen with A (1-7) induced high levels of SIgA-anti-gp120 antibodies at vaginal and rectal sites. The topical application vaccination strategy elicited only very weak systemic immune responses.

Conclusion: Angiotensin (1-7) is a potent mucosal vaccine adjuvant.

This Commentary is aimed at examining the current attitude of healthcare providers towards pathogenic fungi, with more emphasis on The Gambia setting, and to make recommendations for better infectious disease diagnosis and management. It is a known fact that fungi are important infectious diseases causative agents, clinicians however hardly request for medical mycology laboratory tests either because they choose to treat empirically or due to lack of competent mycology laboratories around. Various literature reviewed shows that some signs and symptoms of fungal infections are similar to those caused by bacteria and viruses or both; therefore, there are possibilities of misdiagnosis and missed diagnosis of some diseases. Further mycological studies among Gambian population and inclusion of pathogenic fungal investigations in routine disease diagnosis should be considered.

Aim: This study was carried out to determine the presence of TEM and SHV genes in extended- spectrum β-lactamase (ESBL) producing Klebsiella pneumoniae. The study was also aimed to compare results of phenotypic confirmatory double disc diffusion test and genotypic methods.

Materials and Methods: A total of 679 strains of Klebsiella pneumoniae were selected for the study from June 2012-December 2013. Kirby – Bauer disk diffusion method was performed to determine the antibiotic resistance pattern. Screened for ESBL and confirmed by phenotypic confirmatory disc diffusion test (PCDDT). 100 randomly selected isolates were investigated for the presence of TEM and SHV genes via Polymerase chain reaction (PCR) using two different sets of primers. Multiplex PCR was also performed for the same.

Results: Phenotypic confirmatory test was able to detect ESBL production in 90.13% of Klebsiella pneumoniae isolates. Among the two ESBL genotypes, the most prevalent genotype was found to be TEM. Majority of ESBL producing isolates possess both ESBL genes.

Conclusion: Multiplex PCR can be used as a rapid method to identify common genes (TEM and SHV) responsible for extended spectrum beta lactamase production in Klebsiella pneumoniae. It will prove valuable for surveillance and for determining the line of treatment against drug resistant organisms, thus saving precious time and resources. PCDDT results correlated with genotypic method in all the tested strains.

Introduction: Bacterial meningitis is one of the top ten causes of death amongst children under 5 years in Zimbabwe. Optimizing the identification of the etiologic agents of bacterial meningitis leads to better management of patients. The objective of this study was to compare the effectiveness of latex agglutination (LA), culture and Polymerase Chain Reaction (PCR) as diagnostic methods in the detection of Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus agalactiae and Haemophilus influenzae in paediatric cerebral spinal fluids (CSF) specimens at Harare Children`s Hospital (HCH).

Methodology: Specimens from 162 clinically suspected paediatric cases of bacterial meningitis were processed by cell count, Gram stain, culture, latex agglutination and PCR.

Results: Forty-nine (30.2%) suspected cases were positive for at least one of the four bacterial organisms. The latex agglutination test was positive in 33/49 (67.3%) cases, PCR was positive in 37/49 (75.5%) and culture was positive for 17/49 (34.7%) cases. Streptococcus pneumoniae was the predominant pathogen detected in 29 of the 49 positive cases (59.2%) followed by S. agalactiae detected in 11/49 (22.4%) cases. Haemophilus influenzae was detected in 7/49 (14.3%) cases while N. meningitidis accounted for 2/49 (4.1%) positive cases. Thirty-three (20.4%) CSF samples tested positive with the latex agglutination test. This increased the number of organisms above that detected by culture by 16/49 (32.6%). Polymerase chain reaction detected 37 CSF samples increasing the number of organisms detected by culture by 20/49 (40.8%).

Conclusion: Bacterial meningitis mainly caused by Streptococcus pneumoniae is prevalent among children in Zimbabwe and coupling of culture and non-culture methods can improve detection of the disease.

There is a need for rapid, practical and accurate tuberculosis diagnostic tools that are adapted to resource-poor settings in order to ensure that those affected receive proper and timely treatment. Light-Emitting-Diode microscopy (LED) has recently been endorsed by the WHO for diagnosis of TB in these countries. A much recent smear diagnosis method, PREVI Fluo TB by using LED microscopy, has been made available. However, due to the novelty of the method, there is no information available on the specificity and sensitivity when compared to established methods such as the ordinary LED-Auramine O or the classical widely used Ziehl- Neelsen (ZN) in TB positive persons. This study was undertaken to compare the sensitivity, specificity, positive predictive value and negative predictive value of PREVI Fluo TB stain with ZN method and Auramine O-LED microscopy taking culture as reference. A prospective cross sectional study was conducted in St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia. Spot- Morning-Spot sputum samples from 248 TB suspected study participants were collected. The smear detection rate of PREVI Fluo TB, ZN, Auramine O and culture were found to be 35 (14.1%), 24(9.7%), 44(17.7%) and 30(12.1%) respectively. The sensitivity of the PREVI Fluo TB method was 76.67%, better than ZN and slightly less than Auramine O which were 59.07% and 78.13% respectively. Nevertheless, the specificity (94.5%) was lower than ZN (96.79%) and higher than Auramine O (91.2%). The negative likelihood ratio of PREVI Fluo TB, ZN, and Auramine O methods were 0.25, 0.45, and 0.24 respectively. The PREVI Fluo TB method had a PPV of 65.71% which is higher than the Auramine O (56.82%) but with a comparable NPV (96.71% and 96.57% respectively). The respective agreements of the ZN, Auramine O and PREVI Fluo TB methods with the gold standard were K=0.585, K=0.621 and K=0.664. There was a substantial agreement of PREVI Fluo TB result with ZN (k=0.636) and Auramine O methods (K=0.745).Given the practical benefits of PREVI Fluo TB for TB diagnosis, and comparable accuracy to the current standard of Auramine O fluorescence method and the gold standard culture, PREVI Fluo TB should be considered by TB diagnostic laboratories, as an alternative diagnostic tool for conventional Auramine O fluorescent stain.

Background: Human Metapneumovirus (hMPV) is a member of Paramyxoviridae family. It is an important viral pathogen of respiratory tract infections among children. Therefore, the aim of this study is to determine the incidence of hMPV infections among children less than 5 years of age with respiratory tract infections at the pediatric hospital in Sulaimani city of Iraq. Also, this study aims to evaluate the different diagnostic methods for the detection of this virus.

Method: Nasopharyngeal swabs and throat swabs were collected from 300 hospitalized children with respiratory infections under 5 years of age between April 2011 and March 2012. Each sample was used for hMPV detection by conventional reverse transcriptase (RT-PCR) and direct fluorescent assay (DFA). A questionnaire which was designed for acute respiratory tract infections among hospitalized children was also included.

Results: Human Metapneumovirus was detected in 16% by RT-PCR and 14.7% by DFA. Autumn – winter period was the most common season for hMPV infections with its peak occurrence in January and February.

Conclusions: hMPV is an important pathogen associated with RTIs in children. RT-PCR is highly sensitive and specific for the detection of hMPV than antigen detection methods used for the diagnosis of hMPV viruses.

Introduction: With the increase in prevalence of HIV/AIDS in the world, infection by CMV became a serious public health problem because of the immunodeficiency caused by HIV and the reduction of TCD4+ cells. Objective: Clinical-epidemiological and laboratory aspects of patients were evaluated, which were admitted in a public hospital in the Amazon Region, Belém-Pará, Brazil. Methods: We collected clinical and epidemiological data by questionnaires and medical records, and whole blood for detection of anti-CMV antibodies by ELISA; and the method of Polymerase Chain Reaction in Real Time (qPCR) for detecting viral load. Results: The socioeconomic data indicated high frequency of individuals with incomplete level of basic education (35.3%) and low income (57.7%). Important comorbidities were found by using medical records; pulmonary tuberculosis (19.9%), toxoplasmosis (19.5%), extrapulmonary tuberculosis (14.5%) and diarrheal syndrome (14.1%) occurred more frequently. According to the serological analysis it was observed that only 2.1 of patients had acute infection profile ( IgG+IgM+), while in qPCR more than 50% of patients had high viral load (M =107,479.48 copies/ ml). During this study, 49 patients died, 63.3% were co-infected by HIV/CMV detected using molecular method. It was observed the highest occurrence of CMV-infected individuals when the TCD4 lymphocytes were <100cells/mm3. There were significant differences between molecular data and serological results (Z=12.98, p<0.0001). Conclusions: Molecular methods are the most appropriate technique to help in the clinical diagnosis of secondary CMV infection in immunodeficiencies and the reduction of CD4+<100/mm³ cells is an important risk factor that predisposes people with HIV/AIDS to opportunistic infections.

Food borne diseases/illnesses (food borne infections) are global public health problem both in developed and developing countries such as Nigeria. Food handlers play an important role in the transmission of food-borne diseases. This research work is aimed to determine the prevalence of salmonellosis among food handlers and its implications on the health of food consumers in Lagos, Southwest Nigeria. Two hundred and thirty five (235) blood samples were collected into EDTA bottles from the food handlers at various locations in Victoria Island (Lagos Island) and Bariga (Lagos mainland) which were analyzed using standard methods. Questionnaires were distributed and collated among 235 respondents (food handlers) to test their knowledge on food safety. The results showed that 74 (31.5%) of the studied population had either previous or recent Salmonella infection as indicated by IgG and IgM anti-Salmonella immunoglobulin while 161 (68.5%) had neither recent nor previous infection. Ninety three (93) respondents were males while One hundred and forty two (142) were females of active working age bracket of 11- 60 years old. Among 93 males screened, 26(28.0%) were infected, 67(72.0%) were not infected while 48(33.8%) females were infected out of 142 females screened for Salmonella enterica serovar Typhi and Paratyphi infections. Regression and T-test statistical analysis reviewed that since F cal>F tab (1.776>0.969) and t cal>t tab (6.5>5.0), it can be concluded that food handlers were not responsible for food borne infections but potential risk factors in Lagos, Southwest, Nigeria.

Type I IFNs is vital for host defense against viral and bacterial infections. In addition, type I IFNs are also acknowledged to be involved in many immunoregulatory processes, such as NK cell activation and proliferation/survival of CD8+ T cells.

A 60 year old male presented with frequent episodes of nasal obstruction and epistaxis since 1 year. Strawberry appearance mass was observed in the left nostril, suspected to be rhinosporidiosis. Rhinosporidiosis is a chronic granulomatous, infective disease caused by Rhinosporidium seeberi having been known for more than hundred years. The lesion produces bulky, friable mucosal polyps commonly in the nasal cavity and nasopharynx. He gave history of bathing in ponds. He was treated by local surgical excision.

Background: There is evidence that symptom screening for TB in HIV positive individuals misses the appropriate investigative procedures to confirm for proper diagnosing of TB. High value should be placed in ensuring that TB is diagnosed early in HIV positive individuals, which have an increased likelihood of having undetected TB and high risk of poor health outcomes in the absence of early diagnosis and treatment. Objective: The aim of the study was to determine the prevalence of TB among HIV positive individuals with asymptomatic states at St. Paul’s Hospital millennium Medical College Addis Ababa, Ethiopia. Methods: A cross-sectional study was conducted from May to August, 2014 at SPHMMC. The study included 95 (34 male and 61 female) HIV positive individuals with no TB symptoms (current cough, fever, night sweat, and weight loss). Structured questionnaire was used to collect socio-demographic and clinical related data. The prevalence of TB was determined on the basis of AFB, Xpert MTB/RIF findings and diagnosis with chest X-ray. Result: Out of the 95 participants, the prevalence of undiagnosed Tuberculosis among asymptomatic HIVpatients was 1.1%. The socio-demographic characteristics and related risk factors were not significantly associated with TB finding rate by smear positive and Xpert assay. Our finding also showed a 27% abnormal chest X- ray suggestive of TB. In these HIV positive participants, presence of a patient with previous TB history was significantly abnormal by chest X-ray finding than a patient without TB history. Conclusion: The present finding of asymptomatic undiagnosed Pulmonary TB among HIV-patient is 1.1% (both with AFB and Xpert) in the study area. This showed there is a chance of transmissions of TB to contacts before the proper diagnosis and treatment is made. While the symptom screening algorithm missed the 1.1% TB cases, the AFB technique was able to detect the asymptomatic and missed TB case that was also detected by Xpert assay. TB control programs must consider TB disease prevalence when estimating the possible performance of any screening algorithm. National TB control program should weigh the risks, benefits and cost of screening all asymptomatic and symptomatic HIV infected individuals for TB by Xpert assay.