Tobramycin,amikacin, sissomicin,and gentamicin resistant Gram-negative rods.

Sensitivities to gentamicin, sissomicin, tobramycin, and amikacin were compared in 196 gentamicin-resistant Gram-negative rods and in 212 similar organisms sensitive to gentamicin, mainly isolated from clinical specimens. Amikacin was the aminoglycoside most active against gentamicin-resistant organisms, Pseudomonas aeruginosa, klebsiella spp, Escherichia coli, Proteus spp, Providencia spp, and Citrobacter spp being particularly susceptible. Most of the gentamicin-resistant organisms were isolated from the urine of patients undergoing surgery. Gentamicin was the most active antibiotic against gentamicin-sensitive E coli, Proteus mirabilis, and Serratia spp. Pseudomonas aeruginosa and other Pseudomonas spp were most susceptible to tobramycin.     

Some Metabolic and Biochemical Characteristics of Representative Microbial Isolates from Vacuum-packaged Beef

Some of the metabolic and biochemical characteristics of 105 organisms isolated at 4° from meat matured in vacuo at 0–2° for 0–9 weeks were studied. Proteolysis was noted in Pseudomonas spp., Achromobacter spp. and Gram negative, fermentative organisms, mainly in aerobic and low oxygen environments. Fewer organisms hydrolysed beef fat than hydrolysed tributyrin. While representatives of most of the major groups of organisms dissimilated mono- and di-saccharides, more complex carbohydrates were less readily attacked. Only Gram negative, fermentative organisms showed decarboxylase activity on amino acids. There is evidence that Pseudomonas spp. can survive in an anaerobic environment, although their metabolism is less vigorous.     

The incidence of Bdellovibrio spp. in man-made water systems: coexistence with legionellas

Bdellovibrios have been isolated from surface waters but there are no reports of its occurrence in mains water supplies. One hundred and thirty five water samples from 81 sources were examined for the presence of Bdellovibrio bacteriovorus and Legionella spp. Bdellovibrios were isolated by a double-layer agar technique with two strains of Legionella pneumophila serogroup 1 as the host organisms. Bdellovibrio spp. were isolated from 57.8% and Legionella spp. from 9.5% of the samples. The two species occurred together in 4.4% of samples. The incidence of Bdellovibrio spp. and its occurrence with legionellas in man-made water systems is discussed.     

Comparison of methods for isolation of dematiaceous fungi from nature

Direct plating and animal inoculation techniques were compared for effectiveness in isolating dematiaceous fungi from nature. The direct plating technique involved comparison of aqueous and mineral oil extraction of the samples with subsequent plating on Mycobiotic and Sabhi agar. Twenty four different organisms were recovered from 19 samples using both extraction procedures and both media. Dematiaceous fungi isolated by direct plating were Alternaria alternata, Cladosporium spp., Exophiala jeanselmei, Wangiella dermatitidis and 6 unidentified organisms. Direct plating resulted in more isolations of dematiaceous fungi partly because of the frequent isolations of A. alternata and W. dermatitidis. Both more and a larger variety of organisms were recovered on Mycobiotic than on Sabhi agar. The aqueous extraction of samples resulted in more direct plating isolations of fungi than oil extraction.Only dematiaceous fungi were isolated with the animal inoculation techniques. Fungi isolated from hamsters included Cladosporium spp., Exophiala spinifera, Phialophora verrucosa, Rhinocladiella sp. and 3 unidentified organisms. Fungi isolated by the mouse inoculation technique included Bispora betulina, Cladosporium spp., W. dermatitidis and 1 unidentified organism. In general there was variation in the types of organisms isolated from the same samples depending on the isolation procedure used.     

The incidence of Bdellovibrio spp. in man-made water systems: coexistence with legionellas

Bdellovibrios have been isolated from surface waters but there are no reports of its occurrence in mains water supplies. One hundred and thirty five water samples from 81 sources were examined for the presence of Bdellovibrio bacteriovorus and Legion-ella spp. Bdellovibrics were isolated by a double-layer agar technique with two strains of Legionella pneumophila serogroup 1 as the host organisms. Bdellovibrio spp. were isolated from 57·8% and Legionella spp. from 9·5% of the samples. The two species occurred together in 4·4% of samples. The incidence of Bdellovibrio spp. and its occurrence with legionellas in man-made water systems is discussed.     

The microbial flora of herring fillets after storage in carbon dioxide, nitrogen or air at 2°C

Herring fillets from the Baltic Sea were stored in glass vessels in air, nitrogen or carbon dioxide (CO₂) at 2°C and the microbial development was studied. The microbiological shelf-life of the herring (the time to reach 10⁷ organisms/g) was prolonged by a factor of 3.5 in CO₂ as compared to air. The corresponding factor in nitrogen was 1.5. The microflora of fresh and spoiled herring was classified. The initial microflora was dominated by coryneforms, Flavobacterium spp., Moraxella -like organisms and Pseudomonas spp. The spoilage-flora in air (after 9 d) was dominated by Pseudomonas spp. and Moraxella -like organisms, and in nitrogen (14 d) Enterobacteriaceae, Vibrionaceae and Lactobacillus spp. were dominant. Homofermentative Lactobacillus spp. were the only organisms isolated from fillets stored in CO₂ (28 d). It was concluded that storing fresh fish in pure CO₂ at low refrigeration temperatures is a method with industrial potential. The method (1) improves the microbiological stability and (2) reduces the microbiological health hazards of the fish.     

Die Isolierung bodenbewohnender Feinde des Maisbranderregers Ustilago maydis

The Isolation of Soil-Inhabiting Enemies of Ustilago maydis
Using sporidial lawns of Ustilago maydis in water agar layers as indicator plates 2 organisms could be isolated from soil samples which produce plaques. These organisms were identified as Acanthamoeba polyphaga and Myxococcus spp. Both organisms control populations of Ustilago maydis in sterile soil too.
The isolation method may be gainfully used in the search for further organisms with more specific potential for the biological control of Ustilago maydis .     

The Fungal and Bacterial Flora of Stored White Cabbage

1. The predominant organisms isolated from the outer wrapper leaves of freshly harvested white cabbages were: bacteria, yeasts, Alternaria spp., Aureobasidium pullulans, Botrytis cinerea, Cladosporium spp. and Penicillium spp.
2. Few qualitative or quantitative changes were seen in the leaf surface flora during storage at 2°C for up to 33 weeks.
3. Numbers of bacteria, particularly fluorescent and pectolytic pseudomonads, were considerably higher on cabbages drenched with fungicide or water than on corresponding undrenched cabbages.     

The prevalence of opportunistic pathogens associated with intraoral implants

Aims: The aim of this study was to determine the prevalence and proportions of opportunistic pathogens harboured on orthodontic retainers. Methods and Results: First, Staphylococcus spp. and Candida spp. were isolated from the retainer’s inner surface and from other mucosal surfaces of the subject’s mouth by routine bacterial culture. The prevalence and proportions of these micro‐organisms on retainers was compared in different areas of the mouth within a group of retainer wearers, and mucosal carriage was compared to a group of nonretainer wearers. Staphylococcus spp. were isolated from 50% of the retainers and comprised on average 8·4% of the viable microbiota. Candida spp. comprised 0·13% of the viable microbiota and were recovered from 66·7% of the retainers. Neither genus was isolated from nonretainer wearers. Second, the two most commonly worn retainers manufactured from different materials were sampled; again Staphylococcus spp. and Candida spp. were recovered; however, no statistical differences were observed between the devices. Conclusions: Opportunistic, nonoral, pathogenic micro‐organisms were recovered from orthodontic retainers. Significance and Impact of the Study: It is possible that an orthodontic retainer could be a reservoir for opportunistic pathogens and act as a source of cross‐, self‐ and re‐infection.     

Biofilms as major sources of Legionella spp. in hydrothermal areas and their dispersion into stream water

Abstract Water and biofilms from two hydrothermal areas in central Portugal, and one hydrothermal area in New Mexico, USA, were examined for Legionella spp. In general, Legionella spp were isolated in higher numbers from biofilms than from water, although one biofilm with a temperature of 50°C, did not yield isolates of these organisms. In one area L. pneumophila serogroup (sg) 3 constituted the major population in the thermal discharge by the stream and the biofilm below it; however, L. pneumophila sg 1 was predominant in the sediments of the stream bed with minor thermal springs below the main discharge and in the water downstream. No Legionellae were isolated from water upstream of the hydrothermal area indicating that the thermal area was the source of the organisms in the stream water. In the other two hydrothermal areas, L. pneumophila sg 1 constituted the major population isolated, whereas L. pneumophila sg 3 was absent or isolated in low numbers. Isolates of L. micdadei were also recovered from one hydrothermal area, while ‘ L. londoniensis ’ was isolated from another.     

The role of anaerobic bacteria in chronic suppurative otitis media in children: Implications for medical therapy

This review describes the microbiology, diagnosis and medical management of chronic suppurative otitis media (CSOM) in children highlighting the role of anaerobic bacteria. In studies that employed adequate method for recovery of anaerobic bacteria polymicrobial aerobic and anaerobic flora was isolated from over half of the children with CSOM. The predominant aerobic isolates were Staphylococcus aureus and Pseudomonas aeruginosa and the most frequently isolated anaerobic organisms were Peptostreptococcus, Fusobacterium spp. and pigmented Prevotella and Porphyromonas spp. Several studies illustrated the efficacy of anti-infective agents effective against anaerobic bacteria in the treatment of CSOM. The medical therapy of CSOM should be directed at the eradication of the pathogenic aerobic and anaerobic organisms.     

The Significance of Propionibacterium Species and Micrococcus lactilyticus to the Ensiling Process

The fermentation of lactic acid by two Propionibacterium spp. and by Micrococcus lactilyticus was examined in simulated silage. Fermentation occurred in silages which achieved a low pH (<4·0) but this resulted only in a small rise in pH and a secondary clostridial fermentation did not occur. Lactic acid-fermenting organisms resembling Propionibacterium spp. were isolated from authentic silages but not from fresh grass.     

Comparison of three enrichment media for the isolation of Campylobacter spp. from foods

AIM: This study compared the performance of three Campylobacter enrichment broths: Bolton broth (BB), Campylobacter Enrichment broth (CEB) and Preston broth (PB). METHODS AND RESULTS: Pure cultures of target and competitor organisms, and naturally-contaminated food samples, were used to establish the performance of these media. In pure culture the PB supported the growth of the greatest number of strains of Campylobacter spp. but failed to inhibit some competitor organisms. The CEB showed the opposite result, inhibiting all 15 competitor organisms used but failing to support the growth of five Campylobacter strains. By comparison, BB showed the best compromise between inhibition of competitors and growth of Campylobacter. CONCLUSIONS: Plates inoculated with BB and CEB food enrichments resulted in more Campylobacter growth than those inoculated with PB, which supported significantly less typical growth (P < or = 0.001). The most common competitor organism isolated from PB was Escherichia coli, and Pseudomonas spp. were frequently isolated from BB and CEB. Both BB and CEB were better than PB for the isolation of Campylobacter from naturally-contaminated foods, although BB yielded more confirmed Campylobacter growth than CEB. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlighted differences in performance of media used to isolate Campylobacter spp. from foods.     

Comparison of virulence factors and R plasmids of Salmonella spp. isolated from healthy and ill swine.

The antibiotic resistance and virulence profiles of Salmonella spp. isolated from healthy (group 1) and ill (group 2) swine were compared. Parameters studied included colicin and siderophore production; mannose-sensitive hemagglutination of erythrocytes; resistance to the lethal effect of serum complement; resistance to antibiotics; and the transmissibility of these characteristics to recipient organisms. Group 1 (19 isolates) had 14 serotypes, and group 2 (20 isolates) had 2 serotypes. Isolates from group 2 were resistant to more antibiotics and had a greater ability to hemagglutinate erythrocytes and transfer R plasmids to recipient organisms, but a lesser ability to produce siderophore than group 1. All 39 isolates resisted the lethal effects of serum complement. Colicin was produced by 1 of 19 from group 1 and 0 of 20 from group 2. A donor Escherichia coli isolated from a pig with enteritis transferred R plasmids to 62% of group 1 and 0% of group 2 Salmonella spp. when they were used as recipient organisms. A transconjugant from the mating of donor E. coli to a group 1 Salmonella spp. was further able to pass an R plasmid to recipient E. coli and salmonellae. Plasmid isolation from group 1 yielded 1 of 19 strains with a 56-megadalton plasmid, while 20 of 20 strains from group 2 contained three to five plasmids from 2.4 to 60 megadaltons in size.     

Comparison of virulence factors and R plasmids of Salmonella spp. isolated from healthy and ill swine

The antibiotic resistance and virulence profiles of Salmonella spp. isolated from healthy (group 1) and ill (group 2) swine were compared. Parameters studied included colicin and siderophore production; mannose-sensitive hemagglutination of erythrocytes; resistance to the lethal effect of serum complement; resistance to antibiotics; and the transmissibility of these characteristics to recipient organisms. Group 1 (19 isolates) had 14 serotypes, and group 2 (20 isolates) had 2 serotypes. Isolates from group 2 were resistant to more antibiotics and had a greater ability to hemagglutinate erythrocytes and transfer R plasmids to recipient organisms, but a lesser ability to produce siderophore than group 1. All 39 isolates resisted the lethal effects of serum complement. Colicin was produced by 1 of 19 from group 1 and 0 of 20 from group 2. A donor Escherichia coli isolated from a pig with enteritis transferred R plasmids to 62% of group 1 and 0% of group 2 Salmonella spp. when they were used as recipient organisms. A transconjugant from the mating of donor E. coli to a group 1 Salmonella spp. was further able to pass an R plasmid to recipient E. coli and salmonellae. Plasmid isolation from group 1 yielded 1 of 19 strains with a 56-megadalton plasmid, while 20 of 20 strains from group 2 contained three to five plasmids from 2.4 to 60 megadaltons in size.     

Survey of co-infection by Salmonella and oxyurids in tortoises

ABSTRACT: BACKGROUND: Salmonella spp. and oxyurids are among the most prevalent bacterial and parasitic agents in reptiles. These organisms are routinely isolated in healthy tortoises, although heavy infections may cause significant pathology. Tortoises are considered a common source of reptileassociated salmonellosis, an important zoonosis reported worldwide. A survey of the prevalence of almonella spp. and oxyurids in 53 tortoises was conducted in southern Italy and a possible correlation between the two pathogens was therefore investigated. RESULTS: Salmonella spp. and oxyurids were detected with a prevalence of 49.1 and 81.1%, respectively. A significant positive correlation between Salmonella spp. and oxyurids was demonstrated. However, confounding factors related to husbandry could have been involved in determining this correlation. CONCLUSIONS: Our results suggest that caution should be exercised in translocation, husbandry, and human contact with tortoises and other exotic pets. Further studies on the epidemiology, molecular characterization and pathogenesis of Salmonella and oxyurids are needed to assess the actual impact of these organisms, as single or associated infections, on tortoises and on other exotic pets.     

The aerobic psychotrophic populations on meat and meat contact surfaces in a meat production system and on meat stored at chill temperatures

At a city abattoir, a wholesaler and 10 different supermarkets, surface microbiological samples were taken of carcasses, hands and apron fronts of members of staff and equipment (mincers and saws). In addition, minced meat, packaged and displayed in chilled cabinets, was also sampled. Carcasses, personnel surfaces and equipment were monitored by a modified agar sausage technique. From each of the highest dilution psychotrophic plate counts, five colonies were selected randomly, isolated and identified (1265 in total). Microbes developing on chilled meat were also isolated from other surfaces in the production chain. On chilled meat (51%) and at the abattoir (36%) pseudomonads were the predominant organisms followed by the Gram-positive cocci on chilled meat and by Acinetobacter, Moraxella and Alcaligenes spp. at the abattoir. At the wholesaler Gram-positive cocci (32%) predominated, followed by Alcaligenes, Moraxella and Alcaligenes spp. Pseudomonas, Alcaligenes, Neisseriaceae and related genera, Gram-positive cocci, species from the coryneform groups of bacteria and yeasts were identified from all the surfaces monitored. Identification with the API NE20 was unsatisfactory. Enterbacteriaceae, lactobacilli and endospore-forming bacteria were identified occasionally, but their significance as contaminating organisms seems low. No Salmonella spp. were identified.     

The aerobic psychrotrophic populations on meat and meat contact surfaces in a meat production system and on meat stored at chill temperatures

At a city abattoir, a wholesaler and 10 different supermarkets, surface microbiological samples were taken of carcasses, hands and apron fronts of members of staff and equipment (mincers and saws). In addition, minced meat, packaged and displayed in chilled cabinets, was also sampled. Carcasses, personnel surfaces and equipment were monitored by a modified agar sausage technique. From each of the highest dilution psychrotrophic plate counts, five colonies were selected randomly, isolated and identified (1265 in total). Microbes developing on chilled meat were also isolated from other surfaces in the production chain. On chilled meat (51%) and at the abattoir (36%) pseudomonads were the predominant organisms followed by the Gram-positive cocci on chilled meat and by Acinetobacter, Moraxella and Alcaligenes spp. at the abattoir. At the wholesaler Gram-positive cocci (32%) predominated, followed by Alcaligenes, Moraxella and Alcaligenes spp. Pseudomonas, Alcaligenes, Neisseriaceae and related genera, Gram-positive cocci, species from the coryneform groups of bacteria and yeasts were identified from all the surfaces monitored. Identification with the API NE20 was unsatisfactory. Enterbacteriaceae, lactobacilli and endospore-forming bacteria were identified occasionally, but their significance as contaminating organisms seems low. No Salmonella spp. were identified. and accepted 25 July 1989     

Microbial contamination of hydrogel contact lenses

Bacterial contamination of contact lenses (CLs) may contribute to CL-related corneal infection and inflammation. This study reports CL biota over time during daily and extended wear. Microbial contamination of a 58% water, ionic hydrogel CL and a 38% water, non-ionic hydrogel CL was evaluated in an Australian and an Indian population. Fifty wearers were repeatedly sampled over 18 months. Overnight CL use did not alter the frequency of positive cultures, nor the spectrum of organisms compared with daily CL wear. There were no differences in type and frequency of CL contamination between the CL types. Positive cultures were more frequently recovered from the Indian population compared with the Australian population. Streptococcus spp. and Propionibacterium spp. were more frequently isolated from the Australian population. Fungi and Bacillus spp. were more frequently isolated from the Indian population. Normal CL biota alone cannot explain the increased rate of infection and inflammation in extended wear.     

Ultrastructural evidence for the presence of bacteria, viral-like particles, and mycoplasma-like organisms associated with Giardia spp

Giardia trophozoites and cysts, isolated from mammalian and avian hosts, were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and by fluorescent light microscopy for the presence of microbial symbionts. Mycoplasma-like organisms were observed on the surfaces of trophozoites isolated from the prairie vole, laboratory rat, and beaver. Intracellular bacteria were observed by TEM in the trophozoites and cysts of G. microti and by fluorescence microscopy in trophozoites and cysts of Giardia spp. isolated from beaver, muskrat, great-blue heron, and the green heron. Trophozoites of G. muris from rat small intestine contained viral-like particles measuring 60 nm in diameter. These observations suggest that biological associations between Giardia spp. and diverse microbes may be more common than formerly appreciated. It also raises the possibility of transmission of these apparent symbionts, via the Giardia cyst, to other mammalian hosts including man.