Interactions between Glycopeptides and β-Lactams against Isogenic Pairs of Teicoplanin-Susceptible and -Resistant Strains of
            <i>Staphylococcus haemolyticus</i>

Vignaroli, Carla; Biavasco, Francesca; Varaldo, Pietro E.

doi:10.1128/aac.00260-06

Cited by 5 publications

(4 citation statements)

References 30 publications

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“…However, we recurrently encountered S. haemolyticus group strains originated from apiaries located in study area. S. haemolyticus is the second-most clinically isolated coagulase-negative Staphylococcus bacterium which is considered an important nosocomial pathogen (Vignaroli et al, 2006). Like other coagulase-negative staphylococci, S. hominis has been considered a presumptive and opportunistic pathogen which may occasionally cause infection in patients whose immune systems are compromised (Jiang et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan

Anjum

Shah

Aurongzeb

et al. 2018

Saudi Journal of Biological Sciences

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Gut microbiota has been recognized to play a beneficial role in honey bees (). Present study was designed to characterize the gut bacterial flora of honey bees in north-west Pakistan. Total 150 aerobic and facultative anaerobic bacteria from guts of 45 worker bees were characterized using biochemical assays and 16S rDNA sequencing followed by bioinformatics analysis. The gut isolates were classified into three bacterial phyla of Firmicutes (60%), Proteobacteria (26%) and Actinobacteria (14%). Most of the isolates belonged to genera and families of ,, ,, ,, , and . Many of these bacteria were tolerant to acidic environments and fermented sugars, hence considered beneficial gut inhabitants and involved the maintenance of a healthy microbiota. However, several opportunistic commensals that proliferate in the hive environment including members group and were also identified. This is the first report on bee gut microbiota from north-west Pakistan geographically situated at the crossroads of Indian subcontinent and central Asia.

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Section: Resultsmentioning

confidence: 99%

Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan

Anjum

Shah

Aurongzeb

et al. 2018

Saudi Journal of Biological Sciences

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“…After exposure to increasing daptomycin concentrations, by a procedure successfully used with glycopeptides in previous studies in our laboratory (8), a stable clone with a daptomycin MIC of 4 g/ml was obtained from a daptomycin-susceptible (MIC, 0.5 g/ml) clinical isolate of S. haemolyticus. Vancomycin and teicoplanin MICs also increased from 4 and 8 g/ml in the parent to 8 and 32 g/ml in the laboratory derivative, respectively.…”

Section: Striking "Seesaw Effect" Between Daptomycin Nonsusceptibilitmentioning

confidence: 99%

Striking “Seesaw Effect” between Daptomycin Nonsusceptibility and β-Lactam Susceptibility in Staphylococcus haemolyticus

Vignaroli¹,

Rinaldi²,

Varaldo

2011

Antimicrob Agents Chemother

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The expression "seesaw effect" was originally used by Sieradzki and Tomasz (7), and subsequently by others, to denote a frequently observed inverse relationship between evolving glycopeptide and ␤-lactam MICs in Staphylococcus aureus. The same expression has recently been revived in two interesting studies by Yang et al. (9) and Lee et al. (4) to signify a similar phenomenon, again seen in S. aureus, involving daptomycin instead of glycopeptides. On the other hand, it is well known that S. aureus strains progressively acquiring daptomycin nonsusceptibility during daptomycin exposure also exhibit progressively increasing vancomycin MICs (3, 6).Among coagulase-negative staphylococci, Staphylococcus haemolyticus, second only to Staphylococcus epidermidis in the frequency of its association with human infections (1), is unique in being predisposed to developing glycopeptide resistance and was the first Gram-positive pathogen to acquire such resistance in the 1980s (2).After exposure to increasing daptomycin concentrations, by a procedure successfully used with glycopeptides in previous studies in our laboratory (8), a stable clone with a daptomycin MIC of 4 g/ml was obtained from a daptomycin-susceptible (MIC, 0.5 g/ml) clinical isolate of S. haemolyticus. Vancomycin and teicoplanin MICs also increased from 4 and 8 g/ml in the parent to 8 and 32 g/ml in the laboratory derivative, respectively. The parent strain was both penicillin and methicillin resistant: penicillin and cefoxitin MICs were Ͼ256 g/ml; molecular analysis disclosed a type I SCCmec cassette and regular mec and bla operons; ␤-lactamase production was confirmed by the nitrocefin test. The seesaw effect was striking ( Fig. 1): in the daptomycinnonsusceptible derivative, the penicillin MIC dropped to 0.125 g/ml, in spite of persistent detection of the bla operon and of ␤-lactamase activity, and the cefoxitin MIC dropped to 2 g/ml, despite persistent detection of the mecA gene and the mec operon in a type I SCCmec.Although a number of theories have been advanced to account for the vancomycin/␤-lactam and the daptomycin/ ␤-lactam seesaw effect (7, 9), the underlying mechanisms remain poorly understood. Moreover, while previous hypotheses were essentially aimed at explaining a fall in methicillin resistance, thus largely pointing to some modulation of mecA expression, this case also involves a plunge in penicillin resistance, despite apparently normal-phenotypically and genotypically-␤-lactamase production in the laboratory derivative. In other words, here the seesaw effect needs to be explained in light not only of the mec operon/ PBP2a-mediated ␤-lactam resistance system but also of the bla operon/␤-lactamase-mediated one. It is worth noting that, in a reported case of decreased susceptibility to daptomycin and vancomycin in S. aureus during prolonged therapy, a decreased penicillin MIC was found to be associated with the apparent loss of ␤-lactamase activity (5).

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“…Staphylococcus haemolyticus is the second-most frequently isolated CoNS (S. epidermidis is the first) and it is considered a relevant hospitalacquired pathogen [15]. It is associated with the insertion of foreign devices into the human body like Urinary catheters, prosthetic valves and Cerebrospinal stunts [16,17,18].…”

Section: Althoughmentioning

confidence: 99%

Gram Positive Cocci Associated Urinary Tract Infections, their Prevalence and Antibiotic Susceptibility Patterns

Afolabi Obe,

Mutiu,

Odulate

et al. 2024

S. Asian J. Res. Microbiol.

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Background: Urinary tract infections (UTIs) are the third most common type of infection in humans globally. Gram-positive bacteria are said to be responsible for ten percent of urinary tract (UTI) infections. The study's goal was to profile gram-positive cocci-associated UTIs and their antibiogram, as they were observed at LASUTH. Methods: This was a retrospective assessment of the Medical Microbiology Laboratory records of the LASUTH to review the in vitro antibiotic susceptibility patterns of gram-positive urinary bacterial isolates between April 2020 and March 2021. The bacteria were isolated and identified from routine urine samples using standard bacteriological methods and the API. In vitro antibiotic susceptibility test (AST) was routinely performed by the modified Kirby-Bauer disk diffusion test and susceptibility breakpoints were determined using the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: 2,253 urine samples were processed in the medical microbiology laboratory over the one year and 662 (29.4%) samples yielded Positive cultures. Of the 662 isolates, 494 (74.6%) were gram-negative bacteria. 164 (24.8%) were gram-positive cocci while 4 (0.6%) were gram positive rod. Among the gram-positive cocci’s isolated Enterococcus faecalis had the highest frequency 58 (35.4%). Aminoglycosides (Gentamycin and Amikacin) and Linezolid antibiotics were found to be the most effective drugs against gram-positive cocci bacteria except Enterococcus spp. For empirical treatment of Enterococcus spp in our facility Fosfomycin and Tigecycline are the best options, while for Streptococcus agalactiae associated UTI, Amikacin, Cefuroxime, Linezolid, and levofloxacin can be used for empirical treatment. Conclusion: The prevalence rate of gram-positive cocci associated UTI in this study was 7.3% (164/2253). The emergence of drug resistance in these pathogens to commonly used antibiotics is a thing of concern. Therefore, efficient antimicrobial stewardship programmes must be in place.

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Interactions between Glycopeptides and β-Lactams against Isogenic Pairs of Teicoplanin-Susceptible and -Resistant Strains of Staphylococcus haemolyticus

Cited by 5 publications

References 30 publications

Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan

Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan

Striking “Seesaw Effect” between Daptomycin Nonsusceptibility and β-Lactam Susceptibility in Staphylococcus haemolyticus

Gram Positive Cocci Associated Urinary Tract Infections, their Prevalence and Antibiotic Susceptibility Patterns

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