Prevalence Of Bacterial Species Research Articles

Period prevalence and etiology of subclinical mastitis in Awassi sheep in southern Jordan

To investigate the period prevalence, etiology and some epidemiological features of subclinical mastitis in Awassi ewes from the southern part of Jordan, milk samples from 318 lactating ewes were aseptically collected for bacterial and somatic cell counts (SCC) tests. Milk samples were collected at monthly intervals. The period prevalence of subclinical mastitis was 18.3% and the prevalence within each flock remained relatively constant throughout the study period. A significant association ( P<0.001) was observed between the occurrence of subclinical mastitis and the age of ewe. Presence of teat lesions has no impact on the prevalence of subclinical mastitis. The prevalent bacterial species isolated from mammary glands with subclinical mastitis were Staphylococcus aureus (39%), Streptococci (25%), Escherichia coli (19.6%) and coagulase-negative Staphylococci (17.9%). Coagulase-negative Staphylococci were the most prevailing isolates from samples that showed negative SCC results.

Prevalent bacterial species and novel phylotypes in advanced noma lesions.

The purpose of this study was to determine the bacterial diversity in advanced noma lesions using culture-independent molecular methods. 16S ribosomal DNA bacterial genes from DNA isolated from advanced noma lesions of four Nigerian children were PCR amplified with universally conserved primers and spirochetal selective primers and cloned into Escherichia coli. Partial 16S rRNA sequences of approximately 500 bases from 212 cloned inserts were used initially to determine species identity or closest relatives by comparison with sequences of known species or phylotypes. Nearly complete sequences of approximately 1,500 bases were obtained for most of the potentially novel species. A total of 67 bacterial species or phylotypes were detected, 25 of which have not yet been grown in vitro. Nineteen of the species or phylotypes, including Propionibacterium acnes, Staphylococcus spp., and the opportunistic pathogens Stenotrophomonas maltophilia and Ochrobactrum anthropi were detected in more than one subject. Other known species that were detected included Achromobacter spp., Afipia spp., Brevundimonas diminuta, Capnocytophaga spp., Cardiobacterium sp., Eikenella corrodens, Fusobacterium spp., Gemella haemoylsans, and Neisseria spp. Phylotypes that were unique to noma infections included those in the genera Eubacterium, Flavobacterium, Kocuria, Microbacterium, and Porphyromonas and the related Streptococcus salivarius and genera Sphingomonas and TREPONEMA: Since advanced noma lesions are infections open to the environment, it was not surprising to detect species not commonly associated with the oral cavity, e.g., from soil. Several species previously implicated as putative pathogens of noma, such as spirochetes and Fusobacterium spp., were detected in at least one subject. However, due to the limited number of available noma subjects, it was not possible at this time to associate specific species with the disease.

The human gut flora in nutrition and approaches for its dietary modulation

Summary Concepts about human nutrition have changed significantly during the past few decades, especially in the developed world. There is a shift from the concept of ‘adequate’ to ‘optimal’ nutrition. Thus, diet is not only considered as a means of survival but also as a way of achieving better health and quality of life. The human colonic microbiota has a central role in both health and nutrition. It is unique in complexity and function in the body. More than 500 different bacterial species inhabit the human gut, some considered beneficial, others benign, and others detrimental to host health. There is a delicate balance between the host and the colonic microflora, which not only acts as a protective barrier against infection, but also provides up to 7–10% of the host's daily energy requirements through the fermentation of carbohydrates that escape digestion in the upper gastrointestinal tract. Functional foods targeting the colon focus on the development and prevalence of bacterial species that are considered beneficial to human health, namely, bifidobacteria and lactobacilli. Three approaches for the modulation of human gut flora are reviewed here: probiotics, prebiotics and synbiotics, along with methods for improved characterization and analysis of the intestinal microbiota.

Bacteriological study of bile in patients with cholangitis due to biliary tract obstruction

Acute cholangitis is a serious complication secondary to obstruction of the extrahepatic biliary tract, due mainly to common bile duct stones, but also to malignant tumoral obstruction. The prevalence of bacterial species in the bile of patients with cholangitis have been reported widely. And there was no avalable study in bacteriologic features of bile during past 10 years in Korea. In recent years, increased attention has been focused on the Enterococcus due to increasing in incidence of nosocomial infection and resistance to broad range of antimicrnbial agents of this organism. The purpose of this study wa s to analyse the bacteriologic features of bile in patients with cholangitis. Bacteriological examination w a s made of bile from 356 patients with cholangitis due to biliary tract obstruction, 105 of them with common bile duct stone and 251 of them with malignant disease. Bile specimens were taken during percutaneous transhepatic biliary drainage or endoscopic nasobiliary drainage. The specimens were cultured aerobically and anaerobically and then the antibiotic s~nsitivity test was done. The overall positive culture rates was 81.4%. There was significant difference in positive culture rates between the patients with common bile duct stone and the patients with malignant disease. ( 88.5% vs 78.4%, p<0.05 ) But there was no significant difference in bacteriological features between the patients with common bile duct stone and the patients with malignant disease. The commonly isolated organisms were Enterncoccus ( 21.6% ), E.coli (19.7%), and Klebsiella ( 17.2% ) respectively. The isolation rate of anaerobes were only 2%. The rate of polymicrobial infection was 78.1%. The rate of ampicillin-resistant Enterococcus was 35%. The rate of gentamicin-resistant Enterococcus was 28%. The rates of 3rd generation cephalosporins-resistant Klebsiella were over 30%. This study shows that 1) many microorganisms have resistance to a broad range of antimicrobial agents, and 2) the antibiotic coverage against Enterococcus should be considered for the treatment of cholangitis due to the increasing tendency to Enterococcus infection.

Studies on the microbiological flora of caprine mastitis and antibiotic inhibitory concentrations in Nigeria

The prevalence of bacterial species in each of 103 clinically unaffected and affected caprine udders in the Sahel zone of Nigeria was investigated. A total of 11 genera of bacteria were isolated from unaffected and affected udders. Of the 39 bacterial species isolated from the udders, Acinetobacter anitratus, Bacillus subtilis, Escherichia coli, Pasteurella haemolytica and Staphylococcus aureus occurred significantly (P<0.05) more often than other species in affected compared with unaffected udders. Minimum inhibitory concentrations (MICs) of six antibiotics tested against the significant isolated showed that tylosin had the lowest inhibitory concentrations ranging from 0.10–0.39 μg/ml. Streptomycin and methicillin with MICs of 0.10–0.65 μ/ml and 0.13–1.04 μg/mg, respectively, were lower than bacitracin oxytetracycline and cloxacillin. The need to ascertain antibiotic inhibitory concentrations against significant isolates from different geographical locations for effective chemotherapy and control of caprine mastitis are indicated.

Characterization of Escherichia coli isolated from the tonsils of cattle

During our studies on tonsillar colonization by Pasteurella haemolytica, we consistently found Escherichia coli to be one of the most prominent and prevalent bacterial species in the tonsils of healthy cattle. Since tonsillar isolates have not been characterized, we grouped 124 isolates from 87 healthy cattle from eight sources by hemolytic zone size and by carbon source utilization and probed them for selected virulence genes. They formed 3 groups by hemolytic zone size and 18 groups (of 2 to 31 isolates) by their metabolic patterns. Most groups included isolates from more than one source. Two isolates contained the Shiga-like toxin gene, and nine others contained the F41 accessory gene.

MR/K hemagglutination of Providencia stuartii correlates with adherence to catheters and with persistence in catheter-associated bacteriuria.

Providencia stuartii was the most prevalent bacterial species isolated, for one year, from weekly urine specimens from 51 long-term catheterized patients. Significantly more strains causing bacteriuric episodes of long duration expressed MR/K (mannose-resistant/Klebsiella-like) hemagglutination (74%) than did those causing episodes of short duration (26%; P = .004). Isolates expressing MR/K hemagglutinin bound in higher numbers to catheter material (P = .023) than did those not expressing this hemagglutinin. Significantly more strains causing bacteriuric episodes of short duration expressed the mannose-sensitive (MS) hemagglutinin (43%) than did those causing episodes of long duration (7%; P = .014). Isolates expressing MS hemagglutinin bound significantly more 125I-labeled Tamm-Horsfall protein (THP) than did isolates not expressing this hemagglutinin (P = .0001). Our results indicate that MR/K hemagglutinin plays an important role in the ability of P. stuartii to persist and suggest that MR/K adheres to the catheter. Conversely, MS hemagglutinin binds to THP and may prevent persistence of P. stuartii in the catheterized urinary tract.

Principal beta-lactamases responsible for resistance to beta-lactam antibiotics in urinary tract infections.

Two independent surveys have been conducted to determine the prevalent bacterial species and beta-lactamase types present in clinical populations of gram-negative, ampicillin-resistant isolates. A total of 208 isolates (112 from Nottingham Hospital and 96 from Charing Cross Hospital), all of which had been collected from out-patients suffering from urinary tract infections, were investigated. The incidence of ampicillin-resistant isolates (minimum inhibitory concentrations, 8 micrograms/ml) was 24.1% and 18.8% within the Nottingham and Charing Cross samples, respectively. The surveys gave similar results within the ampicillin-resistant samples. Escherichia coli was the prevalent bacterial species (52.9%), followed by Klebseilla pneumoniae (30.3%). The majority of isolates, at least 54.8% and possibly as high as 74.5%, owed their principal beta-lactamase activity to enzymes mediated by R-plasmids. The most prevalent beta-lactamases were TEM-1 (53.3%), SHV-1 (30.9%), and OXA-1 (11.5%). Positive associations were found between E. coli and TEM-1 or OXA-1 and between K. pneumoniae and SHV-1.

Renal Abscess: A Changing Concept

Gram-negative organisms are now the most prevalent bacterial species found in renal abscesses. We postulate an ascending pathway for establishment of gram-negative abscesses. Voiding cystourethrography should be used in search of reflux. Surgical treatment remains the standard but early diagnosis may increase the effectiveness of parenteral antibiotics as definitive therapy.