医学微生物学与诊断

Objective: Drug resistant Mycobacterium tuberculosis is a public health threat globally. We described the drug resistance pattern of M. tuberculosis to first line anti-TB drugs and the prevalence of Multidrug resistant TB among TB patients at tertiary hospital Nnewi, Nigeria.

Methods: Sputum specimens from 550 suspected TB patients were analyzed for AFB. The smear positive samples were subjected to culture and drug susceptibility testing to first line anti-TB drugs on Lowenstein-Jensen medium.

Result: Out of 180 (32.7%) culture positive samples subjected to DST, 97 (53.8%) were susceptible to all first line anti-TB drugs while 83 (46.1%) were resistant to one or two anti- TB drugs. The level of resistance was significant at p<0.05 identifying three patterns, Mono-drug resistance in 34(18.8%) patients, Multi-drug resistance in 14 (7.7%) and Poly drug resistance in 35 (19.4%) patients. The proportion of TB cases with resistance to single drugs ranged from 5 (2.7%) for rifampicin to 12 (6.6%) for isoniazid and previously treated TB 8 (4.4%) patients was a significant factor (P<0.000) to development of MDR-TB compared to new TB patients 6(3.3%) within the age range of 21-40 years. Other factors such as age, gender and HIV positive status were not significantly associated with the development of any resistance.

Conclusion: The investigation highlights the presence of drug resistant TB with high prevalence of MDR-TB in the studied community. Larger studies are urgently recommended to improve TB clinical management and control efforts.

Background: Clostridium difficile testing for stool specimens transported from remote geographic locations is a challenge due to long transit times that are often at room temperature. The impact of storage at room temperature versus 4°C on Clostridium difficile diagnostic tests during transport of stool samples has not been well studied. Methods: This study assessed the impact of storage at room temperature versus 4°C for up to 72 hours on the stability of glutamate dehydrogenase antigen, Toxin A and B antigens, toxigenic culture and cytopathic effect testing. Twelve diagnostic stool samples that were tested on the day of collection and shown to be C. difficile toxin positive were used for this study. Sample aliquots of each stool were stored at room temperature and 4°C and testing was repeated at 24, 48 and 72 hours. Results: The glutamate dehyrdogenase antigen and toxigenic stool culture tests were shown to be 100% reproducible at room temperature and 4°C for up to 72 hours. Toxin A and B antigen deteriorated to 70% by 72 hours at room temperature but was 90% reproducible if held at 4°C. The cytopathic effect assay was 90% reproducible by 72 hours at room temperature and 4°C. Conclusions: Based on our data we recommend that for laboratories receiving stool samples from remote regions where transit may be prolonged that glutamate dehydrogenase antigen screening followed by nucleic acid amplification testing may be a feasible diagnostic algorithm.

Background: Early appropriate antibiotic therapy improves the prognosis of patients with bloodstream infection (BSI). Our goal was to define the use of antimicrobial agents active against Enterococcus species; we explored the possibility that simple clinical and laboratory parameters may be able to identify those individuals at high risk of suffering BSI caused by Enterococcus species.

Methods: Total of 165169 blood culture bottles from 27360 patients were screened. Patients with blood cultures positive for Gram positive cocci in chain were identified (n=365) and they were classified as having hospital acquired infection (HAI) or community acquired infection (CAI) according to the Centers for Disease Control and Prevention (CDC) criteria. We recorded simple clinical and laboratory parameters (plasma C-reactive protein (CRP) concentration, blood white cell count (WBC), data of systolic and diastolic blood pressure, heart rate, and body temperature) at the time when the blood cultures were drawn. Results: It was found that CAI cases were most often (86%) caused by Streptococcus species but the majority (73%) of HAI episodes were caused by Enterococcus isolates (p<0.001). We also found that combining the data of origin of the infection, age of the patient, and plasma CRP concentration could help to predict the bacterial finding within the CAI category: blood cultures positive for enterococci were mostly encountered among the elderly (>60 years) exclusively with low CRP values. In the HAI category, the bacterial finding was not associated with these parameters.

Conclusion: Our study demonstrates that basic clinical observations and laboratory parameters may effectively guide antibiotic treatment early during the course of BSI caused by Gram positive cocci in chain. These parameters are extremely simple to perform and are readily available in most hospitals. We conclude that clinical evaluation should not be overlooked despite the emergence of novel microbiological methods.

We describe the first case of thrombotic thrombocytopenic purpura (TTP) in a patient with Legionnaires’ disease. TTP was demonstrated by the low level of adams TS13 activity that resolved after plasmapheresis and remained normal in the long-term follow up.

Malaria has been one of the most prominent and ancient disease which has been profiled and studied malaria distribution seasons from September to December following the major rainy seasons from June to August with minor transmission seasons from February to march with some changes from place to place. The primary objective of this study is to determine the prevalence of malaria among patients visiting Nekemte hospital. Across sectional study was conducted to determine the prevalence of malaria among patients visiting Nekemte hospital. For the present study 120 patients were included in this study which was selected by convenient sampling techniques. The data was sorted by hand and using table and the calculation was done by using scientific hand calculator. Results were presented using tables. Two species of malaria, P. falciparum and P. vivax were identified with relatively higher prevalence of P. vivax (59.2%). Educational status, presence of stagnant water and bed net usage had an association with prevalence of malaria. Age and religion had no any association with prevalence of malaria between the age group of 17 to 27 and illiterate patients had relatively higher prevalence of malaria. Malaria infection can be reduced with the help of early treatment and by using bed nets.

Acute respiratory tract infections (ARTI) are the more frequent causes of morbidity and mortality in children. This review was conducted to assess the existing evidence concerning bacterial extracts efficacy in the prevention of pediatric ARTI. The data sources for the identification of clinical trials and reviews included principal bibliographic databases (MEDLINE, Embase, Cochrane Library, PubMed/www.ncbi.nlm.nih.gov). Selected clinical trials only involved children suffering from recurrent ARTI. Bacterial extracts may reduce the incidence of ARTI of about 40% in toddlers (2-5 years), school boys (6-12 years) and children at higher ARTI risk (e.g. children living in orphanages). Among others, the active treatment with OM-85 led to 26, 2% fewer patients with recurrent ARTI. Data from the literature are encouraging, particularly for treatment with OM-85. The strengthening of pre-clinical and clinical research is necessary to allow routine recommendation of bacterial extracts prescription for ARTI prevention in children.

The purpose of this research is to identify nucleotide and amino acid positions are essential for the function of the HA gene and its protein products. A metric for sequence variability was hamming distance, determined for all possible inter-subtype HA sequence pairs of H1N1, H3N2 and H6N1 HA sequences in the complete NCBI HA gene datasets. Almost all (97.22%) of nucleotide positions at which the Hamming distance was zero were in the HA2 domain of the HA gene; the invariant nucleotides occupied second and first codon positions except for a tail-region encoded invariant tryptophan. In contrast with the results at the nucleotide level, the patterns of epitope distribution in the encoded HA proteins were similar except for a 25-amino acid sequence (283-307) in the HA1 region of HA H6N1. These results demonstrate the occurrence of similar organization of immunological epitopic biopatterns in influenza a hemagglutinins at the protein level, even in the face of large differences in the sequences of encoding nucleotides and encoded amino acids.

Abstract
Patients with Liver Cirrhosis (LC) are at high risk of developing bacterial infections.

Pathological

bacterial translocation has been implicated as an important cause of bacterial infection in patients with LC, and Spontaneous Bacterial Peritonitis (SBP) and bacteremia are common and often fatal bacterial infections in these patients. Moreover, the incidence of hepatorenal syndrome is associated with bacterial infections such as SBP; in addition, the syndrome is often fatal in

patients

with LC. The frequency of isolation of multidrug-resistant (MDR) organisms in patients with LC and bacterial infections has been reported to be increasing in recent years, and infections caused by MDR

organisms

appear to be associated with poor prognoses. However, further research is required to better understand bacterial infections in the setting of LC because there remain unresolved problems related to this issue. This review summarizes the frequency, diagnoses, causative organisms, prognoses, and treatment of SBP and bacteremia in patients with LC.

Introduction: Post-sternotomy infection is a serious cause for morbidity and mortality after cardiac surgery. The goal of this study was to evaluate the impact of a microbial sealant on post-sternotomy infections in high risk patients undergoing cardiac surgery. Methods: Between January 2006 and July 2008 a total of 291 consecutive patients underwent cardiac surgery with a Fowler score of at least 10, which indicates high risk patients to develop surgical site infection (SSI). Patients were divided into a control group (n=132) receiving standard institutional preoperative care and a microbial sealant group (n=159) received additionally a microbial skin sealant. Pre- and peri-operative characteristics were examined for both groups. The clinical end-point of this study was freedom of post-sternotomy infection. Results: Follow up was 100% completed. The preoperative risk score of the control and the microbial sealant group were similar, respectively 15.5 ± 4.0 and 15.2 ± 3.8 (p=0.513). Comparing pre- and peri-operative characteristics of both groups, significant higher rates of carotid artery disease (p=0.022) and diabetics (p=0.046) were found in the microbial sealant group. All other pre- and peri-operative characteristics were similar for both groups. The clinical end-point however, showed a significant decrease of SSI in the microbial sealant group 2.5% (n=4) versus the control group 7.6% (n=10), (p=0.045). Conclusions: This study showed that the additional use of a microbial sealant to standard institutional preoperative preparation reduces statistically significant the risk for surgical site infection in high risk patients undergoing cardiac surgery.