Systemic quinolone antibiotics in children: a review of the use and safety

Epidemiology, Incidence of Infection, and Antibiotic Use in Pediatric Traumatic Ear Lacerations

BACKGROUND

The management and use of antibiotics in pediatric ear lacerations lacks standardization. This study sought to provide a comprehensive review of these injuries and assess the impact of administering perioperative antibiotics on the incidence of infections after repair.

METHODS

Retrospective review of all pediatric ear lacerations treated at our institution's emergency department (ED) between 1998 and 2024.

RESULTS

A total of 246 patients (177 boys) were included. Patients aged 0-6 years were most affected (n = 117, 47.6%), with the peak between 2-5 years old (n = 78, 31.7%). Most lacerations were superficial (n = 145, 58.9%), followed by intermediate (n = 62, 25.2%), full thickness (n = 34, 13.9%), and split earlobe defects (n = 5, 2%). Most of the patients (n = 110, 54.7%) were managed by emergency medicine providers. Plastic and reconstructive surgery (n = 34, 16.9%) and otorhinolaryngology (n = 32, 15.9%) consultations were obtained when the lacerations affected cartilage (P < 0.001). Surgical repair included primary closure in 203 (82.5%), with 179 (88.2%) performed under local/topical anesthesia in the ED. Of patients with cartilage lacerations (n = 61), 48 had cartilage repair. Eight patients had preoperative intravenous antibiotics, while 105 (42.7%) received postoperative prophylactic oral antibiotics. Among those with intermediate and full-thickness injuries (n = 96), 67.7% were discharged on prophylactic oral antibiotics. Only 1 case of surgical site infection occurred in a patient with a superficial laceration.

CONCLUSIONS

Pediatric ear lacerations mostly affect boys aged 2-5 years and are usually repaired under local anesthesia in the ED. The incidence of infection is low, and the routine prescription of prophylactic oral antibiotics appears to have a limited impact on the overall incidence of surgical site infection. Further studies are needed to validate these findings.

Characterization of Transferrable Mechanisms of Quinolone Resistance (TMQR) among Quinolone-resistant Escherichia coli and Klebsiella pneumoniae causing Urinary Tract Infection in Nepalese Children

BACKGROUND

Transferrable mechanisms of quinolone resistance (TMQR) can lead to fluoroquinolone non-susceptibility in addition to chromosomal mechanisms. Some evidence suggests that fluoroquinolone resistance is increasing among the pediatric population. We sought to determine the occurrence of TMQR genes among quinolone-resistant E. coli and K. pneumoniae causing urinary tract infections among Nepalese outpatient children (< 18 years) and identify molecular characteristics of TMQR-harboring isolates.

METHODS

We performed antimicrobial susceptibility testing, phenotypic extended-spectrum β-lactamase (ESBL) and modified carbapenem inactivation method tests, and investigated the presence of six TMQR genes (qnrA, qnrB, qnrS, aac(6')-Ib-cr, oqxAB, qepA), three ESBL genes (blaCTX-M, blaTEM, blaSHV), and five carbapenemase genes (blaNDM, blaOXA-48, blaKPC, blaIMP, blaVIM). The quinolone resistance-determining region (QRDR) of gyrA and parC were sequenced for 35 TMQR-positive isolates.

RESULTS

A total of 74/147 (50.3%) isolates were TMQR positive by multiplex PCR [aac(6')-Ib-cr in 48 (32.7%), qnrB in 23 (15.7%), qnrS in 18 (12.3%), qnrA in 1 (0.7%), and oqxAB in 1 (0.7%) isolate]. The median ciprofloxacin minimum inhibitory concentration of TMQR-positive isolates (64 µg/mL) was two-fold higher than those without TMQR (32 µg/mL) (p = 0.004). Ser-83→Leu and Asp-87→Asn in GyrA and Ser-80→Ile in ParC were the most common QRDR mutations (23 of 35). In addition, there was a statistically significant association between TMQR and two β-lactamase genes; blaCTX-M (p = 0.037) and blaTEM (p = 0.000).

CONCLUSION

This study suggests a high prevalence of TMQR among the quinolone-resistant E. coli and K. pneumoniae isolates causing urinary tract infection in children in this area of Nepal and an association with the carriage of ESBL gene. This is a challenge for the management of urinary infections in children. Comprehensive prospective surveillance of antimicrobial resistance in these common pathogens will be necessary to devise strategies to mitigate the emergence of further resistance.

Construction of a Nomogram for Identifying Refractory Mycoplasma pneumoniae Pneumonia Among Macrolide-Unresponsive Mycoplasma pneumoniae Pneumonia in Children

OBJECTIVE

The individualized prediction of treatment regimens of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) is scarce. The aim of this study was, therefore, to evaluate the relevant data of patients and construct a nomogram for identifying refractory Mycoplasma pneumoniae pneumonia (RMPP) among children continued to be treated with macrolide after the confirmation of MUMPP, providing a reference for the choice of treatment regimen.

METHODS

We performed a retrospective study involving 162 children who continued to be treated with macrolide (azithromycin) after the confirmation of MUMPP without antibiotic changes between January 2020 and January 2022. We collected data on clinical feature, hospitalization period, treatments, laboratory data, extrapulmonary symptoms, parapneumonic effusion, and connections with other respiratory pathogens. In addition, the independent risk factors for RMPP were determined through univariate and multivariate analyses, and then a nomogram was constructed and validated.

RESULTS

In this study, the multivariate logistic regression analysis showed that age, leukocyte count, neutrophil proportion, serum procalcitonin, and lactate dehydrogenase were independent risk factors for RMPP. Using the five independent associated factors, the nomogram for identification of RMPP was constructed. Moreover, the area under the ROC curve (AUC) was 0.925 (95% CI: 0.882-0.968) for the nomogram showing excellent discrimination. The calibration curve, close to the 45-degree line, exhibited good calibration of nomogram.

CONCLUSION

We constructed and validated a visual and user-friendly nomogram for individualized prediction of RMPP risk in children who continued to be treated with macrolide after the confirmation of MUMPP based on five variables. According to the nomogram model, continuation of macrolide should be considered rather than second-line antibiotics including tetracyclines (doxycycline or minocycline) and fluoroquinolones for MUMPP children with low predictive values.

Global prevalence of resistance to macrolides in Mycoplasma pneumoniae: a systematic review and meta-analysis

OBJECTIVES

To determine the prevalence of resistance to macrolides in Mycoplasma pneumoniae worldwide.

METHODS

Prior to 12 December 2020, PubMed, Web of Science, Scopus and Embase databases were searched for epidemiological studies of M. pneumoniae resistance. Two reviewers independently extracted data from included studies. The extracted data include sampling population, total sampling number, the number of resistant strains and the molecular subtype of resistant strains. The estimate of resistance prevalence was calculated using the random-effects model.

RESULTS

A total of 17 873 strains were obtained from five continents and reported in 98 investigations between 2000 and 2020, with 8836 strains characterized as macrolide resistant. In summary, macrolide-resistant M. pneumoniae was most common in Asia (63% [95% CI 56, 69]). In Europe, North America, South America and Oceania, the prevalence was 3% [2, 7], 8.6% [6, 11], 0% and 3.3%, respectively. Over the last 20 years, the prevalence of macrolide-resistant M. pneumoniae has remained high in China (81% [73, 87]), with a significant increasing trend in South Korea (4% [1, 9] to 78% [49, 93], P < 0.0001). Furthermore, a point mutation at 2063 from A to G was mostly related to M. pneumoniae macrolide resistance. In terms of clinical outcomes, longer cough (mean difference [MD]: 2.93 [0.26, 5.60]) and febrile days (MD: 1.52 [1.12, 1.92]), and prolonged hospital stays (MD: 0.76 [0.05, 1.46]) might be induced by macrolide-resistant M. pneumoniae pneumonia.

CONCLUSIONS

The incidence of macrolide-resistant M. pneumoniae varies globally, with eastern Asia having a greater degree of resistance. However, attention is also required in other areas, and antibiotic alternatives should be considered for treatment in high-prevalence countries.

Point-of-care molecular diagnosis of Mycoplasma pneumoniae including macrolide sensitivity using quenching probe polymerase chain reaction

Objectives

Macrolides are generally considered to be the drugs of choice for treatment of patients with Mycoplasma pneumoniae infection. However, macrolide-resistant M. pneumoniae has been emerging since about 2000. The Smart Gene^® system (MIZUHO MEDY Co., Ltd., Tosu, Japan) is a novel fully automated system for detection of pathogens using the method of quantitative polymerase chain reaction (qPCR) with QProbe (QProbe PCR). The entire procedure is completed within 50 min and the size of the instrument is small (15 x 34 x 30 cm). The purpose of this study was to evaluate the usefulness of the Smart Gene^® system for detection of M. pneumoniae and detection of a point mutation at domain V of the 23S rRNA gene of M. pneumoniae.

Materials

Pharyngeal swab samples were collected from 154 patients who were suspected of having respiratory tract infections associated with M. pneumoniae.

Results

Compared with the results of qPCR, the sensitivity and specificity of the Smart Gene^® system were 98.7% (78/79) and 100.0% (75/75), respectively. A point mutation at domain V of the 23S rRNA gene was detected from 7 (9.0%) of 78 M. pneumoniae-positive samples by the Smart Gene^® system and these results were confirmed by direct sequencing. The minimum inhibitory concentrations of clarithromycin among the 5 isolates of M. pneumoniae with a point mutation at domain V of the 23S rRNA gene were >64 μg/ml and those among the 33 isolates without a mutation in the 23S rRNA gene were <0.0625 μg/ml.

Conclusion

The Smart Gene^® system is a rapid and accurate assay for detection of the existence of M. pneumoniae and a point mutation at domain V of the 23S rRNA gene of M. pneumoniae at the same time. The Smart Gene^® system is suitable for point-of-care testing in both hospital and outpatient settings.

Detection of antibiotics in the urine of children and pregnant women in Jiangsu, China

Exposure to low concentrations of antibiotics links to multiple health hazards, such as drug resistance of bacteria, and childhood obesity. In this study, seven antibiotics were measured in the urine of 107 children and 126 pregnant women in Jiangsu Province by ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). The overall urinary antibiotics detection rate was 38.6%. Most (98.3%) of the participants' antibiotics concentrations were no more than 10 ng/mL. Children had a significantly higher detection rate than pregnant women (47.7% vs. 31.0%, P = 0.009), as well as the concentration (95th percentile: 6.49 vs. 4.08 ng/mL, P = 0.002). The detection rates of individual antibiotics ranged from 0.4% to 15.0%, and the concentrations ranged from lower than the limit of detection (LOD) through up to 31.96 ng/mL individually. Two or more antibiotics were detected in 11.2% of the urines. Tetracyclines were more frequently detected than phenicols (30.9% vs.12.4%). Oxytetracycline was the most frequently detected (15.0%). Multivariate logistic regression showed that consuming puffed food every day was associated with a significantly increased likelihood of detection, and higher concentration of overall antibiotics, and of doxycycline. Children were more likely to be detected of doxycycline and florfenicol, and to have elevated concentration of doxycycline, compared with pregnant women. This study highlights the relatively heavier antibiotics exposure in children, and a possible impact of puffed food on it, which needs to be warranted in future studies.

Transferable Mechanisms of Quinolone Resistance from 1998 Onward

While the description of resistance to quinolones is almost as old as these antimicrobial agents themselves, transferable mechanisms of quinolone resistance (TMQR) remained absent from the scenario for more than 36 years, appearing first as sporadic events and afterward as epidemics. In 1998, the first TMQR was soundly described, that is, QnrA. The presence of QnrA was almost anecdotal for years, but in the middle of the first decade of the 21st century, there was an explosion of TMQR descriptions, which definitively changed the epidemiology of quinolone resistance. Currently, 3 different clinically relevant mechanisms of quinolone resistance are encoded within mobile elements: (i) target protection, which is mediated by 7 different families of Qnr (QnrA, QnrB, QnrC, QnrD, QnrE, QnrS, and QnrVC), which overall account for more than 100 recognized alleles; (ii) antibiotic efflux, which is mediated by 2 main transferable efflux pumps (QepA and OqxAB), which together account for more than 30 alleles, and a series of other efflux pumps (e.g., QacBIII), which at present have been sporadically described; and (iii) antibiotic modification, which is mediated by the enzymes AAC(6')Ib-cr, from which different alleles have been claimed, as well as CrpP, a newly described phosphorylase.

Therapeutic Efficacy and Safety of Prolonged Macrolide, Corticosteroid, Doxycycline, and Levofloxacin against Macrolide-Unresponsive Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents.

METHODS

We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ≥ 38.0°C at ≥ 72 hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis.

RESULTS

Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups.

CONCLUSION

The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

Research progress on distribution, migration, transformation of antibiotics and antibiotic resistance genes (ARGs) in aquatic environment

Antimicrobial and antibiotics resistance caused by misuse or overuse of antibiotics exposure is a growing and significant threat to global public health. The spread and horizontal transfer of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) by the selective pressure of antibiotics in an aquatic environment is a major public health issue. To develop a better understanding of potential ecological risks die to antibiotics and ARGs, this study mainly summarizes research progress about: (i) the occurrence, concentration, fate, and potential ecological effects of antibiotics and ARGs in various aquatic environments, (ii) the threat, spread, and horizontal gene transfer (HGT) of ARGs, and (iii) the relationship between antibiotics, ARGs, and ARB. Finally, this review also proposes future research direction on antibiotics and ARGs.

Veterinary antibiotics in food, drinking water, and the urine of preschool children in Hong Kong

Due to the harmful effects of veterinary antibiotics (VAs) residues in food on children's health, urine samples from 31 preschool and primary school children were analyzed for 13 common VAs. Samples of raw and cooked pork, chicken, fish, milk and drinking water from the children's living areas were also analyzed for residual VAs. Urinalysis revealed one to four target antibiotics in 77.4% of the sample group, with concentrations as high as 0.36ng/mL. Norfloxacin and penicillin had the highest detection rates (48.4% and 35.5%, respectively), with median concentrations of 0.037 and 0.13ng/mL, respectively. The VA burden of children in HK was lower than that in Shanghai. Enrofloxacin, penicillin, and erythromycin were the most detected VAs in raw and cooked food. Only oxytetracycline was detected in terminal tap water, and none were detected in milk. Tetracycline and doxycycline hyclate were detected in organic eggs (up to 7.1ng/g) and regular eggs (up to 6.6ng/g), which were common in children's diets. Traditional Chinese cooking processes did not completely eliminate VAs, and the concentrations of some VAs increased, especially after frying and roasting. The estimated daily intake (EDI) results show that the contribution of dietary intake and that based on the urine concentrations of VAs were far below the acceptable daily intake (ADI). The EDIs from urine were significantly lower than those based on cooked foods. The highest level of achievement percentage (LAP) based on dietary consumption and urine concentrations were 39.7% and 1.79%, respectively, and thus current levels of exposure to VAs would not seem to pose a risk to children's health. However, harmful effects of residual VAs during developmental periods may occur with exposure to much lower doses than those considered harmful to adults, and further investigation of these emerging pollutants is urgently encouraged.

Population dynamics of enteric Salmonella in response to antimicrobial use in beef feedlot cattle

A randomized controlled longitudinal field trial was undertaken to assess the effects of injectable ceftiofur crystalline-free acid (CCFA) versus in-feed chlortetracycline on the temporal dynamics of Salmonella enterica spp. enterica in feedlot cattle. Two replicates of 8 pens (total 176 steers) received one of 4 different regimens. All, or one, out of 11 steers were treated with CCFA on day 0 in 8 pens, with half of the pens later receiving three 5-day regimens of chlortetracycline from day 4 to day 20. Salmonella was isolated from faecal samples and antimicrobial susceptibility was analysed via microbroth dilution. Serotype was determined by whole-genome sequencing. On day 0, mean Salmonella prevalence was 75.0% and the vast majority of isolates were pansusceptible. Both antimicrobials reduced overall prevalence of Salmonella; however, these treatments increased the proportion of multi-drug resistant (MDR) Salmonella from day 4 through day 26, which was the last day of faecal collection. Only six Salmonella serotypes were detected. Salmonella serotype Reading isolates were extensively MDR, suggesting a strong association between serotype and resistance. Our study demonstrates that the selection pressures of a 3^rd generation cephalosporin and chlortetracycline during the feeding period contribute to dynamic population shifts between antimicrobial susceptible and resistant Salmonella.

Urinary Antibiotics of Pregnant Women in Eastern China and Cumulative Health Risk Assessment

Exposure to antibiotics during pregnancy can pose a systematic effect on human health. A few biomonitoring studies have demonstrated an extensive exposure of children to antibiotics, but there is still a lack of data for pregnant women. To assess the exposure of pregnant women to antibiotics and potential health risk, we investigated 536 pregnant women aged 16-42 years from two geographically different study sites in Eastern China in 2015. We measured 21 antibiotics of five categories (seven fluoroquinolones, three phenicols, four tetracyclines, three macrolides, and four sulfonamides) in urine using the isotope dilution ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. The hazard index (HI) was calculated on the basis of estimated daily exposure dose and acceptable daily intakes. A total of 16 antibiotics were found in urine, with detection frequencies between 0.2 and 16.0%. Antibiotics were overall detected in 41.6% of urine, and two or more antibiotics were detected in 13.1% of urine. Ciprofloxacin, ofloxacin, and trimethoprim were most frequently detected in urine, with detection frequencies between 10 and 20%. The majority of the antibiotics tested had an estimated daily exposure dose less than 1 μg/kg/day, and 4.3% of pregnant women had a HI value of more than 1. These findings indicated that pregnant women were frequently exposed to antibiotics and some individuals were in the potential risk of adverse microbiological effects induced by antibiotics.

Therapeutic efficacy of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant and macrolide-sensitive Mycoplasma pneumoniae pneumonia in pediatric patients

OBJECTIVE

To clarify therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia and against macrolide-sensitive Mycoplasma pneumoniae (MSMP) pneumonia in pediatric patients.

METHODS

A prospective, multicenter observational study was conducted from July 2013 to August 2015. The therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin were evaluated in 59 patients with pneumonia caused by MRMP and in 50 patients with pneumonia caused by MSMP. In vitro activities of antimicrobial agents against isolates of Mycoplasma pneumoniae were also measured.

RESULTS

Mean durations of fever following commencement of treatment in patients infected with MRMP and MSMP were 5.2 and 1.9 days, respectively (log-rank test, P < 0.0001). Among patients infected with MRMP, mean durations of fever were 4.6, 5.5, 1.0 and 7.5 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P < 0.0001). Among patients infected with MSMP, mean durations of fever were 2.5, 1.7, 0.9 and 4.3 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P = 0.0162). The MIC90s of azithromycin and clarithromycin among the 27 isolates of MRMP were 64 and 256 μg/ml, respectively, and those among the 23 isolates of MSMP were <0.000125 and 0.001 μg/ml, respectively. The MIC90s of minocycline and tosufloxacin among the 27 isolates of MRMP were 1.0 and 0.25 μg/ml, respectively, and those among the 23 isolates of MSMP were 1.0 and 0.5 μg/ml, respectively.

CONCLUSION

Both minocycline and tosufloxacin showed good in vitro activities against MRMP. Minocycline, but not tosufloxacin, shortened the duration of fever in pediatric patients infected with MRMP compared to the duration of fever in patients treated with macrolides.

Safety Concerns Surrounding Quinolone Use in Children

Fluoroquinolones are highly effective antibiotics with many desirable pharmacokinetic and pharmacodynamic properties including high bioavailability, large volume of distribution, and a broad spectrum of antimicrobial activity. Despite their attractive profile as anti-infective agents, their use in children is limited, primarily due to safety concerns. In this review we highlight the pharmacological properties of fluoroquinolones and describe their current use in pediatrics. In addition, we provide a comprehensive assessment of the safety data associated with fluoroquinolone use in children. Although permanent or destructive arthropathy remains a significant concern, currently available data demonstrate that arthralgia and arthropathy are relatively uncommon in children and resolve following cessation of fluoroquinolone exposure without resulting in long-term sequelae. The concern for safety and risk of adverse events associated with pediatric fluoroquinolone use is likely driving the limited prescribing of this drug class in pediatrics. However, in adults, fluoroquinolones are the most commonly prescribed broad-spectrum antibiotics, resulting in the development of drug-resistant bacteria that can be challenging to treat effectively. The consequence of misuse and overuse of fluoroquinolones leading to drug resistance is a greater, but frequently overlooked, safety concern that applies to both children and adults and one that should be considered at the point of prescribing.

Antibiotics in Drinking Water in Shanghai and Their Contribution to Antibiotic Exposure of School Children

A variety of antibiotics have been found in aquatic environments, but antibiotics in drinking water and their contribution to antibiotic exposure in human are not well-explored. For this, representative drinking water samples and 530 urine samples from schoolchildren were selected in Shanghai, and 21 common antibiotics (five macrolides, two β-lactams, three tetracyclines, four fluoquinolones, four sulfonamides, and three phenicols) were measured in water samples and urines by isotope dilution two-dimensional ultraperformance liquid chromatography coupled with high-resolution quadrupole time-of-flight mass spectrometry. Drinking water included 46 terminal tap water samples from different spots in the distribution system of the city, 45 bottled water samples from 14 common brands, and eight barreled water samples of different brands. Of 21 antibiotics, only florfenicol and thiamphenicol were found in tap water, with the median concentrations of 0.0089 ng/mL and 0.0064 ng/mL, respectively; only florfenicol was found in three bottled water samples from a same brand, with the concentrations ranging from 0.00060 to 0.0010 ng/mL; no antibiotics were found in barreled water. In contrast, besides florfenicol and thiamphenicol, an additional 17 antibiotics were detected in urine samples, and the total daily exposure doses and detection frequencies of florfenicol and thiamphenicol based on urine samples were significantly and substantially higher than their predicted daily exposure doses and detection frequencies from drinking water by Monte Carlo Simulation. These data indicated that drinking water was contaminated by some antibiotics in Shanghai, but played a limited role in antibiotic exposure of children.

[Management of multidrug-resistant tuberculosis]

The emergence of drug-resistant TB in many countries has become a major public health problem and an obstacle to effective tuberculosis control. Multidrug-resistant tuberculosis (MDR-TB), which is most often the result of poor adherence, is a particularly dangerous form of tuberculosis because it is caused by bacilli resistant to at least isoniazid and rifampicin, the two most effective anti-tuberculosis drugs. Techniques for rapid diagnosis of resistance have greatly improved the care of patients by allowing early treatment which remains complex and costly establishment, and requires skills and resources. The treatment is not standardized but it includes in all cases attack phase with five drugs (there must be an injectable agent and a fluoroquinolone that form the basis of the regimen) for eight months and a maintenance phase (without injectable agent) with a total duration of 20 months on average. Surgery may be beneficial as long as the lesions are localized and the patient has a good cardiorespiratory function. Evolution of MDR-TB treated is less favorable than tuberculosis with germ sensitive. The cure rate varies from 60 to 75% for MDR-TB, and drops to 30 to 40% for XDR-TB. Mortality remains high, ranging from 20 to 40% even up to 70-90% in people co-infected with HIV.

Characteristics of hospitalized children infected with macrolide-resistant Mycoplasma pneumoniae

BACKGROUND

The aim of this study was to clarify retrospectively the characteristics of children hospitalized for respiratory tract infection caused by macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae).

METHODS

Children who were hospitalized for respiratory tract infection due to M. pneumoniae were enrolled in this study. The diagnosis of M. pneumoniae infection was made on the grounds of polymerase chain reaction results.

RESULTS

Thirty-three children were hospitalized due to lower respiratory tract infection with M. pneumoniae. Of the 33 children, 31 (median age five years) were identified as being infected with macrolide-resistant M. pneumoniae (A2063G:30, A2064G:1) by sequence analysis. Of the 31 children infected with macrolide-resistant M. pneumoniae, 21 (68%) had received 14- or 15-membered macrolide antibiotics and four (13%) had received minocycline before hospitalization. During hospitalization, minocycline was administered to 16 (52%) of the 31 children infected with macrolide-resistant M. pneumoniae. Of the 20 children infected with macrolide-resistant M. pneumoniae under eight years of age, six (30%) were treated with minocycline during hospitalization. The difference in total febrile days between children receiving minocycline treatment before hospitalization and children not receiving minocycline treatment was three days.

CONCLUSIONS

The majority of hospitalized children with respiratory tract infection due to macrolide-resistant M. pneumoniae infection was of preschool age and had received 14- or 15-membered macrolide antibiotics before hospitalization. Because macrolide-resistant M. pneumoniae is widespread in Japan, the administration of minocycline as a second-line antibiotic in children under eight years of age cannot be withheld when clinical symptoms do not improve with macrolide antibiotics.

Oxidation of quinolones with peracids (an in situ EPR study)

4-Oxoquinoline derivatives (quinolones) represent heterocyclic compounds with a variety of biological activities, along with interesting chemical reactivity. The quinolone derivatives possessing secondary amino hydrogen at the nitrogen of the enaminone system are oxidized with 3-chloroperbenzoic acid to nitroxide radicals in the primary step while maintaining their 4-pyridone ring. Otherwise, N-methyl substituted quinolones also form nitroxide radicals coupled with the opening of the 4-pyridone ring in a gradual oxidation of the methyl group via the nitrone-nitroxide spin-adduct cycle. This was confirmed in an analogous oxidation using N,N-dimethylaniline as a model compound. N-Ethyl quinolones in contrast to its N-methyl analog form only one nitroxide radical without a further degradation.

Systemic use of fluoroquinolone in children

Fluoroquinolones are an important class of antibiotics that are widely used in adult patients because of their broad spectrum of activity, good tissue penetration, and oral bioavailability. However, fluoroquinolone use in children is limited because juvenile animals developed arthropathy in previous experiments on fluoroquinolone use. Indications for fluoroquinolone use in patients younger than 18 years, as stated by the U.S. Food and Drug Administration, include treatment of complicated urinary tract infections and postexposure treatment for inhalation anthrax. In Korea, the systemic use of fluoroquinolones has not been approved in children younger than 18 years. Although concerns remain regarding the adverse musculoskeletal effects of fluoroquinolones in children, their use in the pediatric population has increased in many circumstances. While pediatricians should be aware of the indications and adverse effects of fluoroquinolones, recent studies have shown that the risk for musculoskeletal complications in children did not significantly increase following fluoroquinolone treatment. In addition, fluoroquinolones may be particularly helpful in treating multidrug-resistant infections that have not responded to standard antibiotic therapy in immunocompromised patients. In the present article, we provide an updated review on the safety and current recommendations for using fluoroquinolones in children.

Pattern of bacterial isolates in the middle ear discharge of patients with chronic suppurative otitis media in a tertiary hospital in North central Nigeria

BACKGROUND

Otitis media (OM) is a major health problem in both developed and developing countries.

OBJECTIVE

To determine the pattern of bacterial isolates in patients with chronic suppurative otitis media(CSOM) in Ilorin, Nigeria.

METHODS

A prospective study carried out in University of Ilorin Teaching Hospital, Nigeria among consenting patients with CSOM attending the ENT clinic over a period of 7months. Informed consent was obtained from the patients or caregivers and approval for the study obtained from ethical committee. Structured questionnaire was administered and microbiological analysis done, data obtained was entered into SPSS statistical software and results presented in tables and figures.

RESULTS

A total of 134 patients aged 5-64yrs with chronic suppurative otitis media were interviewed with a mean age of 17.0 (S.D. =15.1±1.30). About 55.2% of the respondents were under 10yrs. Seventy-two (53.7%) of the respondents were males with M:F=1.2:1. The gram stain showed predominantly gram negative organisms (71.6%). Pseudomonas aeruginosa was the commonest middle ear pathogenic organism identified and the sensitivity pattern highly favoured ciprofloxacin

CONCLUSION

CSOM is still a childhood problem among the under tens' more prevalent among males and the commonest agent is Pseudomonas aeruginosa. Ciprofloxacin is still the most sensitive antibiotics in vitro.

Acute bacterial meningitis in infants and children

Bacterial meningitis continues to be an important cause of mortality and morbidity in neonates and children throughout the world. The introduction of the protein conjugate vaccines against Haemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis has changed the epidemiology of bacterial meningitis. Suspected bacterial meningitis is a medical emergency and needs empirical antimicrobial treatment without delay, but recognition of pathogens with increasing resistance to antimicrobial drugs is an important factor in the selection of empirical antimicrobial regimens. At present, strategies to prevent and treat bacterial meningitis are compromised by incomplete understanding of the pathogenesis. Further research on meningitis pathogenesis is thus needed. This Review summarises information on the epidemiology, pathogenesis, new diagnostic methods, empirical antimicrobial regimens, and adjunctive treatment of acute bacterial meningitis in infants and children.

X-ray structure of the ternary MTX.NADPH complex of the anthrax dihydrofolate reductase: a pharmacophore for dual-site inhibitor design

For reasons of bioterrorism and drug resistance, it is imperative to identify and develop new molecular points of intervention against anthrax. Dihydrofolate reductase (DHFR) is a highly conserved enzyme and an established target in a number of species for a variety of chemotherapeutic programs. Recently, the crystal structure of Bacillus anthracis DHFR (baDHFR) in complex with methotrexate (MTX) was determined and, based on the structure, proposals were made for drug design strategies directed against the substrate-binding site. However, little is gleaned about the binding site for NADPH, the cofactor responsible for hydride transfer in the catalytic mechanism. In the present study, X-ray crystallography at 100 K was used to determine the structure of baDHFR in complex with MTX and NADPH. Although the NADPH binding mode is nearly identical to that seen in other DHFR ternary complex structures, the adenine moiety adopts an off-plane tilt of nearly 90 degrees and this orientation is stabilized by hydrogen bonds to functionally conserved Arg residues. A comparison of the binding site, focusing on this region, between baDHFR and the human enzyme is discussed, with an aim at designing species-selective therapeutics. Indeed, the ternary model, refined to 2.3 A resolution, provides an accurate template for testing the feasibility of identifying dual-site inhibitors, compounds that target both the substrate and cofactor-binding site. With the ternary model in hand, using in silico methods, several compounds were identified which could potentially form key bonding contacts in the substrate and cofactor-binding sites. Ultimately, two structurally distinct compounds were verified that inhibit baDHFR at low microM concentrations. The apparent Kd for one of these, (2-(3-(2-(hydroxyimino)-2-(pyridine-4-yl)-6,7-dimethylquinoxalin-2-yl)-1-(pyridine-4-yl)ethanone oxime), was measured by fluorescence spectroscopy to be 5.3 microM.

Crystal structure of the anthrax drug target, Bacillus anthracis dihydrofolate reductase

Spores of Bacillus anthracis are the infectious agent of anthrax. Current antibiotic treatments are limited due to resistance and patient age restrictions; thus, additional targets for therapeutic intervention are needed. One possible candidate is dihydrofolate reductase (DHFR), a biosynthetic enzyme necessary for anthrax pathogenicity. We determined the crystal structure of DHFR from B. anthracis (baDHFR) in complex with methotrexate (MTX; 1) at 2.4 Angstrom resolution. The structure reveals the crucial interactions required for MTX binding and a putative molecular basis for how baDHFR has natural resistance to trimethoprim (TMP; 2). The structure also allows insights for designing selective baDHFR inhibitors that will have weak affinities for the human enzyme. Additionally, we have found that 5-nitro-6-methylamino-isocytosine (MANIC; 3), which inhibits another B. anthracis folate synthesis enzyme, dihydropteroate synthase (DHPS), can also inhibit baDHFR. This provides a starting point for designing multi-target inhibitors that are less likely to induce drug resistance.