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Benzylpenicillin (Penicillin G)
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Alasdair M. Geddes, Ian M. Gould, Jason A. Roberts, Jason A. Trubiano, M. Lindsay Grayson
Gram-negative anaerobic cocci such as Veillonella spp. were usually sensitive to Pen G (Sutter and Finegold, 1976) but resistance is now described (Reig et al., 1997), usually in the absence of beta-lactamase production, and may be quite common (Nyfors et al., 2003). Up to 68% of Veillonella spp. in 49 healthy infants were penicillin resistant, resistance increasing with age, although MICs were clustered around the 2 μg/ml breakpoint; but strains with an MIC > 8 μg/ml have been described (Reig et al., 1997). Ready et al. (2004) found that 79% of 24 V. parvula isolates obtained from children penicillin resistant, but they had been selected for study as they were amoxicillin resistant. A strain of Acidaminococcus fermentans was described as penicillin resistant due to class A beta-lactamase production (Gallan et al., 2000).
Control of the Large Bowel Microflora
Published in Michael J. Hill, Philip D. Marsh, Human Microbial Ecology, 2020
Bohumil S. Drasar, April K. Roberts
Numerically, the most important genus of intestinal bacteria in animals and humans are the Gram-negative Bacteroides. Among the Gram-positive, nonsporing rods several genera are numerically important in the gut. Obligate anaerobic types include Eubacterium sp. and Bifidobacterium sp., such as the B. bifidum and B. infantis found in the feces of breast-fed infants. The genus Lactobacillus contains many species occurring in the gut of most warmblooded animals. Although numerically important throughout the alimentary tract, their ecological significance has not been conclusively elucidated. Several types of spore-forming rods and cocci are normal inhabitants of the gut. The genus Clostridium is probably the most ubiquitous. C. perfringens, C. bifermentans, and C. tetani are found regularly, albeit in relatively low numbers, in the lower gut of animals and are of significance in human and veterinary medicine. The presence of the aerobic Bacillus genus is thought to be the result of contamination of the environment. Facultative and obligate anaerobic Gram-positive cocci are numerically important in the gut. The strict anaerobes include Peptostreptococcus, Ruminococcus, Megaspnaera elsdenii, and Sarcina ventriculi. The facultatively anaerobic streptococci are well represented by many species from Lancefield group D including Streptococcus faecalis, S. bovis, and S. equinus, and some from group K such as S. salivarius which is usually associated with the mouth. Gram-negative anaerobic cocci include Veillonela and Acidaminococcus. Although they are not numerically important, the Gram-negative facultative anaerobic rods include a number of very important pathogens. Members of the Enterobacteraceae, particularly E. coli, are usually thought of as the characteristic intestinal bacteria. Several types of spirochaete can be seen in the gut of healthy animals and their status in the human gut is uncertain.
A case study of salivary microbiome in smokers and non-smokers in Hungary: analysis by shotgun metagenome sequencing
Published in Journal of Oral Microbiology, 2020
Roland Wirth, Gergely Maróti, Róbert Mihók, Donát Simon-Fiala, Márk Antal, Bernadett Pap, Anett Demcsák, Janos Minarovits, Kornél L. Kovács
Megasphaera, the other genus of increased abundance in the saliva of current smokers belongs in the phylum Firmicutes. Megasphaera are Gram-negative anaerobic cocci, which reside in the upper digestive tract of adults, contributing to the microbial community of tongue dorsum, tonsils and saliva [86]. In line with our results, an increase in relative abundance of Megasphaera was observed in oropharyngeal samples and esophageal samples of smokers relative to non-smokers [97,98]. Perhaps the smoky environment may confer a growth advantage for Megasphaera [98]. Dysbiotic diseases, including periodontitis and bacterial vaginosis were also associated with higher relative abundance of Megasphaera species [99,100]. Moreover, the genus Megasphaera was associated with human papillomavirus (HPV) positive head and neck squamous carcinoma and lung cancer [101,102].