Medical Microbiology & Diagnosis

Although rabies infects all warm blooded animals in nature, the primary hosts are domestic and wild dogs. Many other susceptible hosts include cats, foxes, and bats many of which also serve as reservoir and source of infection to other animals including human and livestock. Incidence of rabies in livestock is a re-emerging global phenomenon being reported in both rabies endemic and hitherto dog rabies free countries. We report cases of rabies in cattle, sheep and goat in Nigeria, highlighting the risk factors of human exposure due to handling and consumption the carcases. The food animals exposed to rabies exhibited the clinical signs including hyperactivities, aggression and drooling of saliva and were confirmed positive for rabies by Fluorescent antibody test. This implies that excess dog rabies goes into atypical hosts like these food animals. Though these animals are dead-end hosts, the consequence is that more human exposure, through these atypical means, is possible by direct bites, contact with saliva or other body fluids from slaughter and consumption of these animals. Control of rabies in domestic dogs and vaccination of other live stocks like cows, sheep and goats, is necessary to prevent untold economic loses and risks of humans exposure to rabies.

Background: Hepatitis B virus surface antigen (HBsAg) is used for the detection of Hepatitis B virus (HBV) infection and to predict disease progression.

Objectives: The main objective of this study was to observe the pattern of HBV viral load levels among people in terms of age and sex distribution in Bangladesh.

Method: Blood specimen was collected from 585 objects with HBsAg Positive and assayed for the quantity of hepatitis B virus using PCR based technique.

Results: It is found from the study that the mean viral load was 353,500,000 DNA copies/ml for 20-35 age group, 249,300,000 DNA copies/ml for 35-50 age group and 104,800,000 DNA copies/ml for 50-65 age group. The median HBV viral loads for male and female were 58,494 and 103,287 DNA copies/ml, respectively.

Conclusion: High viral load was observed in the 21-35 and 36-50 age group while females are at most risk due to HBV infection as their viral load is higher compared to male.

Fungal brain abscess is a rare entity especially in an immune competent host. Here we report a rare case of Candida brain abscess in a 19 year old immune competent patient. The diagnosis was made by CT scan of brain and confirmed by microbiological culture. The patient did not respond to surgical intervention and antimicrobial therapy and succumbed to his illness.

The frequency of fungal infections, especially of Invasive Fungal Infections (IFIs), has risen dramatically in recent years, and has high morbidity and mortality. Early and accurate diagnosis is important for timely implementation of antifungal therapy and decreasing the unnecessary use of toxic antifungal agents. Conventional microbiological, histological and radiological techniques remain the cornerstone of diagnosis but are insensitive and have a limited impact on clinical decision-making. There is always a need to characterize fungi quickly and accurately which can be done by rapid diagnostic techniques like antigen detection and molecular techniques. This is a brief review of all the microbiological techniques- conventional and recent alternative techniques especially elaborating antigen detection and molecular techniques which are available for diagnosis of fungal infections.

The aim of this review article is to compare molecular typing methods of methicillin resistant Staphylococcus aureus (MRSA) strains. Resistance to methicillin and other beta-lactam antibiotics is caused by the mecA gene, which is situated on a mobile genetic element, the Staphylococcal Cassette Chromosome mec (SCCmec). While hospital acquired (HA)-MRSA strains are typically multi-resistant, community associated (CA)-MRSA strains are by large more susceptible to many antibiotics. More resently multi-resistant livestock associated (LA)-MRSA strains have been recovered from bovine mastitis, but these strains are only prevalent in certain high-risk groups of workers in direct contact with live animals. The epidemiology of MRSA might be investigated by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing, DNA microarray hybridisation and SCCmec typing. Until recently the most useful technique was the PFGE, which has high discriminatory index, but technically difficult and slow, the portability is limited, and multiple nomenclature and misclassification of some lineages also can occur. The mec (SCCmec) typing has standard nomenclature wich able to distinguish between the HA-MRSA and CA-MRSA strains. The spa typing might be a useful tool for epidemiological studies of MRSA, due to its rapidity, accessibility, high throughput, and standardized nomenclature. The MLST has high discriminatory power, defines core genetic population and also has portability and standard nomenclature, but the weaknessess of this method are the low throughput and high cost. Though, the DNA miroarray hybridization test is the most modern technique, which able to detect of presence of a huge number of genomic loci, but due to the high cost and complexity not preferred in routine practice. Considering all data of these molecular techniques, the most recommended methods are the spa and staphylococcal cassette chromosome mec (SCCmec) typing. Both are informative enough to define particular strain characteristics and utilise standardised nomenclatures, making them applicable globally. Continuous efforts to follow up the changing epidemiology of MRSA infection in humans and animals are necessary, not only for effective infection control and appropriate antibiotic treatment, but also monitoring the evolution of the MRSA clones.

Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) Infections are considered public health problems. The coinfection HIV/HCV is common in individuals exposed to parenteral exposure, and HVC has emerged as the leading cause of deaths among HIV-1-seropositive patients. The treatment of HIV/HCV coinfected people should be able to suppress viral replication for both viruses, with the purpose of to improve the immunological response and include liver damage. These two aspects should be associated with a high safety profile, because the toxicity of antiretroviral drugs used to treat HIV in HIV/HCV coinfected people, can lead them to death. The management of the treatment of patients is needed to monitor and, if possible, prevent complications related to adverse effects.

Purpose: We studied the risk factors for the acquisition of Ventilator-associated Pneumonia (VAP) caused by Pseudomonas aeruginosa in two Intensive Care Units (ICU).

Methods: We carried out a case-control study, from January 1, 2006 through June 30, 2008. We defined as CASES patients with Pseudomonas aeruginosa VAP and CONTROLS patients with VAP caused by other Gramnegative bacteria.

Results: The study of risk factors for the development of VAP by Pseudomonas aeruginosa showed that three of them are referred to the pre-ICU admission history of the patient: hospitalization during previous 6 months, admission from other wards/hospitals instead of domicile provenance (p<0.01) and duration of pre-ICU hospitalisation (p<0.01, at multivariate analysis: OR 2.09 IC95% 1.18-3.72). Analysis of antibiotic prescription before the development of VAP showed as independent risk factor the number of different antibiotic classes prescribed to patients or rather the complexity of antibiotic exposure (OR 2.3 IC95% 1.14-4.67). Analysis of mortality revealed a non-significant difference between VAP caused by Pseudomonas or other Gram-negative bacteria, although our data suggest an association between MDR Pseudomonas infection and higher mortality (p=0.03).

Conclusion: Our study offers points that can contribute to improve the empiric antibiotic prescription in ICU. In presence of in-hospital patients presenting with a previous history of antibiotic prescription, with a complex clinical condition preceding ICU admission or with a prolonged ventilatory assistance, presenting with signs or symptoms of infection, should be advisable to prescribe a therapy with a specific activity against Pseudomonas aeruginosa.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is usually susceptible to a variety of non-beta-lactam drugs. These isolates commonly display SCCmecIV and are associated with community-acquired infections. More recently, CA-MRSA has been isolated from health-care-associated diseases. We categorize isolates resistant only to oxacillin or oxacillin plus no more than 3 non-beta-lactam antibiotics according to clinical and epidemiological characteristics, from a hospital in Porto Alegre, and performed a combination of molecular techniques including mecA, SCCmec, Panton-Valentine leukocidin (PVL) detection and Pulsed-field gel electrophoresis (PFGE). A total of twenty-five patients with non-multidrug-resistant MRSA were studied. Nineteen (76%) came from skin and soft tissue infections. All isolates presented SCCmec type IV (being 19/25 IVc) whereas the PFGE profile most frequently found was OSCP-like (15/25). The presence of international clones USA400, USA300 was also verified. Comparing the results of clonal type with source, origin, type of SCCmec, presence the PVL gene and antimicrobial resistance we observed that OSCP-like PFGE profile was associated with skin and soft tissue infections (P=0.0012) and that this clonal group was strongly associated with the presence of PVL gene (P<0.001). This study shows a clonal diversity of CA-MRSA and strengths the concept that these isolates emerged globally from different backgrounds.