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Acute Otitis Media
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
In persistent or recurrent bacterial AOM, repeat culture of middle ear aspirates has failed to grow pathogenic bacteria in 30–50% of patients, implying that inflammation may persist despite the eradication of the infecting organism. The role of biofilms is the subject of intensive study at present. The spectrum of organisms is similar to that in isolated episodes. In the 1980s H. influenzae was the most common organism identified in persistent or recurrent AOM, but this has been replaced by drug-resistant pneumococcus. After antibiotic treatment for recurrent AOM it is now estimated that 50% of H. influenzae are beta-lactamase producing. A similar proportion of pneumococci are penicillin-resistant.16 Penicillin resistance in pneumococci results from decreased penicillin-binding protein on the bacterial cell walls so reducing the affinity for penicillin-related drugs, but this means that resistance may often be overcome by increasing drug dosage. This is not the case with beta-lactamase producing organisms. Most M. catarrhalis are now beta-lactamase producing.
Cefuroxime
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
Given its activity against S. pneumoniae, H. influenza, and M. catarrhalis, cefuroxime has been extensively used for the empirical treatment of CA-RTIs. However an increase in resistance rates among common pathogens causing RTIs has been observed, potentially limiting its use in some countries. Given the importance of pneumococcal pneumonia, studies evaluating serious pneumococcal infections are of great importance. Yu et al. (2003) evaluated the outcome of patients with pneumococcal bloodstream infection. Patients who were infected with pneumococci that were not susceptible to cefuroxime (median MIC by E test, 3 µg/ml; median MIC by broth dilution assay, 8 µg/ml) but who were treated with cefuroxime, experienced a significantly higher mortality rate (4 of 11 [36.4%] died) than patients in whom cefuroxime was used and the organism was susceptible (4 of 53 [5.8%] patients died; p = 0.02) (Yu et al., 2003). In this study, most patients who were treated with cefuroxime received the standard dose at 750 mg every 8 hours. These results suggest that the activity of cefuroxime against cefuroxime-resistant S. pneumoniae (MICs ≥ 4 µg/ml) using a parenteral dose of 750 mg every 8 hours is likely to be suboptimal. (In contrast, penicillin was effective regardless of whether there was apparent penicillin “resistance.”) It is not certain whether larger doses of cefuroxime might have a superior effect. In a small evaluation of three patients with bacteremic pneumococcal pneumonia in Spain, i.v. cefuroxime (1500 mg every 8 hours) was effective therapy for cefuroxime-resistant strains (cefuroxime MICs 2–4 µg/ml) (Caballero-Granado et al., 1996).
Bacteriology of Ophthalmic Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Arumugam Priya, Shunmugiah Karutha Pandian
The emerging antibiotic resistance and production of numerous virulence factors potentiates the infectious nature of Staphylococcus spp. in ocular infections. Staphylococcus spp. can evolve very rapidly against a range of antibiotics. S. aureus isolates, which are known as MRSA that are resistant to methicillin, are commonly resistant to other beta-lactam antibiotics such as penicillin, carbapenem, cephalosporin, and monobactam (Rayner and Munckhof, 2005). The antibiotic susceptibility of CoNS is unpredictable. Penicillin resistance is extremely common worldwide. Hence, penicillinase-resistant beta-lactam antibiotics such as flucloxacillin and oxacillin are commonly used for first-line therapy. Most of the strains of CoNS, CA-MRSA, and HA-MRSA were found to be multiresistant. In an antibiotic susceptibility study conducted in the year 2012, MRSA strains were found to be susceptible to vancomycin, teicoplanin, and gentamicin (Kotlus et al., 2006; Hsiao et al., 2012). Ocular MRSA strains were highly resistant to fluoroquinolones including the fourth generation (Kotlus et al., 2006). CA-MRSA and HA-MRSA strains were found to be highly sensitive to cotrimoxazole, rifampicin, fusidic acid, and minocycline. The frequently used topical antibiotic chloramphenicol was relatively found to be sensitive to almost all Staphylococcus spp. (Wong et al., 2017). S. aureus develops resistance against antibiotic with various mechanisms including enzymatic inactivation of antibiotics with penicillinase and aminoglycoside-modifying enzymes, altering the target and thereby decreasing the affinity of antibiotics, trapping of antibiotics and efflux pumps. Horizontal gene transfer, spontaneous mutations, and positive selection can also confer antibiotic resistance (Pantosti et al., 2007) (Figure 11.2).
The impact of vaccination on the burden of invasive pneumococcal disease from a nationwide surveillance program in Lebanon: an unexpected increase in mortality driven by non-vaccine serotypes
Published in Expert Review of Vaccines, 2022
Lina Reslan, Nour Youssef, Celina F. Boutros, Aia Assaf-Casals, Danielle Fayad, Sarah Khafaja, Fata Akl, Marc Finianos, Amena A. Rizk, Rouba Shaker, Alissar Zaghlout, Mireille Lteif, Bassam El Hafi, Mohammad Bahij Moumneh, Rita Feghali, Soha Ghanem, Tamima Jisr, Gilbert Karayakoupoglou, Malak Naboulsi, Monzer Hamze, Salam Samad, Elie Khoury, Ricardo Sarraf, Marwan Osman, Elie Bou Raad, Hadi El Amin, Ibrahim Abadi, Hicham Abdo, Marwan Chedid, Fatima Chamseddine, Angelique Barakat, Mohammad Houmani, Antoine Haddad, Georges Abdel Nour, Jacques E. Mokhbat, Ziad Daoud, Mohamad El-Zaatari, Elie Salem Sokhn, Nada Ghosn, Walid Ammar, Randa Hamadeh, Ghassan M. Matar, George F. Araj, Ghassan S. Dbaibo
We explored the changes in antimicrobial resistance trends over the three eras across the different age groups. We first analyzed the change in penicillin resistance and found that it decreased significantly across all three age groups over the study eras (p-value = 0.002, OR = 0.567, 95%CI = [0.396–0.813]) (Figure 3A). When the PCV13 and the PCV7 eras were compared, there was a pronounced decrease in penicillin resistance among the 6–60 and the > 60 years age groups. (Figure 3A). Whereas 14% of isolates from the age group ≤ 5 were penicillin resistant, only 2.4% were resistant in the 6–60 years and none in the >60 years age groups in the PCV13 era (p-value = 0.038, OR = 0.376, 95% CI = [0.149–0.949]) (Figure 3A). The proportion of isolates resistant to penicillin remained the highest in the ≤ 5 years age group across the three eras with 25.4%, 23.2% and 14% respectively. In contrast, the resistance rates to erythromycin in the ≤ 5 years age group were somewhat stable over the three study eras unlike the other age groups where a fluctuating trend was evident in the 6–60 and > 60 years age groups (Figure 3B). Resistance rates to clindamycin decreased significantly in the oldest age group across the 3 eras (p-value = 0.047, OR = 0.390, 95%CI = [0.154–0.988]) but in the youngest age group they remained steady (27–30%) across all eras. (Figure 3C).
A profile of delafloxacin in the treatment of adults with community-acquired bacterial pneumonia
Published in Expert Review of Clinical Pharmacology, 2022
Silvia Gómez-Zorrilla, Elena Sendra, Juan P. Horcajada
The currently unmet need for therapies to treat community-acquired bacterial pneumonia (CABP) is related to the increase in antimicrobial resistance in Gram-positive cocci causing CABP, such as S. pneumoniae. According to EARS-Net data from 2020, whereas penicillin resistance rates in several European countries (Spain, Germany, Belgium, Sweden) were below 5%, in others, such as Greece (66.3%), Romania (48%), Italy (29.5%) and Bulgaria (28.1%), the rates were very high [24]. In the United States, penicillin resistance has decreased in recent years due to the effect of pneumococcal vaccination, although current rates are around 9 cases per 100,000 habitants in adults older than 65 years [25]. In addition, while MRSA-CABP is infrequent in European countries, rates in the US are higher. In a multinational study performed in 2015, investigators found that 4.8% of CAP patients in North America who had at least one diagnostic test for a pathogen had MRSA. The prevalence of MRSA in this cohort (range 6.1–16.4%) was highest in North America (16.4%), followed by South America (15.3%), and Oceania (7.7%) [26].
Predictors of mortality in invasive pneumococcal disease: a meta-analysis
Published in Expert Review of Anti-infective Therapy, 2021
Tuna Demirdal, Pinar Sen, Busra Emir
Inappropriate antimicrobial therapy leads to increased antimicrobial resistance and mortality due to treatment failure [23]. It has been shown that antimicrobial resistance tends to increase over the years and presents a major threat to the treatment success in IPD [10,24]. We demonstrated that only penicillin resistance has an influence on mortality in our study. In addition, we demonstrated that inappropriate initial antibiotherapy usage increased mortality, while penicillin or amoxicillin use decreased mortality in the treatment of IPD. We also identified an increased mortality in patients receiving vancomycin for the treatment of IPD. Our finding may have an indirect effect on the choice of vancomycin for antibiotic treatment in critically ill patients or in patients with treatment failure whose prognosis is more guarded. Because, the studies included in our meta-analysis were not adjusted according to the severity of the disease. Another possible explanation for poor vancomycin therapeutic outcomes in IPD may be attributed to the inability to reach effective concentrations due to the higher vancomycin minimum inhibitory concentration within the susceptible range. Nevertheless, this result is controversial due to the lack of standardization in terms of disease severity, previous antibiotic use, therapeutic drug monitoring, and pharmacological data regarding vancomycin dosing.