A total of 98 participants (50% men) were evaluated. Table 1 shows the gender, eye laterality, and number of applications by eye. For sex and laterality, the percentage was calculated in relation to the total number of participants. The male prevalence was 50%; both eyes of 50% of patients were included; and three or more applications were administered to both eyes in 80%. Another 16 patients who met the inclusion criteria refused participation and were excluded. Half of the patients had samples collected from both eyes, 23 (23.5%) only from the right eye, and 26 (26.5%) only from the left eye.
A total of 148 samples were collected from these patients. Sixteen samples (10.81%) had negative cultures. In addition to the negative samples, antibiograms were not performed on another 20 cultures (13.51%), totaling 36 samples (24.32%) without antibiograms. A total of 128 (86.48%) samples were collected from patients with at least three previous intravitreal applications and 20 (13.51%) had fewer than three. 50% of the samples were from patients who had one swab collected from each eye at different times, as the intravitreal injections were never administered simultaneously. The culture results grew 20 different microorganisms, the most frequent of which were Staphylococcus sp. (coagulase-negative), S. epidermidis, S. aureus, Corynebacterium sp., and S. haemolyticus (Tables 2, 3). Staphylococcus sp. (coagulase-negative) and S. epidermidis comprised 93.1% and 95.5%, respectively, of the samples.
Table 3 shows that the compositions of the type of culture existing in the same eye presented in decreasing order of frequency, with Staphylococcus sp. (coagulase-negative) the most common.
Tables 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 show the antibiotic sensitivity by microorganism described as antibiotic sensitive, intermediate, or resistant. The percentage was calculated based on the total number of participants who underwent the antibiogram for a given type of culture and had results available.
After positive cultures were identified, antibiograms were performed to determine the sensitivity to amikacin, amoxicillin, ampicillin, azithromycin, cefepime, cefotaxime, ceftriaxone, cefuroxime, ciprofloxacin, clarithromycin, clindamycin, doxycycline, ertapenem, imipenem, erythromycin, streptomycin, gentamicin, levofloxacin, linezolid, oxacillin, penicillin, rifampicin, trimethoprim-sulfamethoxazole, tetracycline, vancomycin, and tobramycin.
All bacteria were sensitive to amikacin (Table 4); the microorganisms resistance to azithromycin were as follows: 93.3% of the samples of S. aureus, 100% of S. capitis, 71% of S. epidermidis, 58.3% of S. haemolyticus, 100% of S. hominis, and 60.8% of Staphylococcus sp. (coagulase negative) (Table 7); all Escherichia coli samples were resistant to cefepime, cefotaxime, and ceftriaxone, and there was 50% of E. coli was resistant (Tables 8, 9, 10); the microorganisms resistant to ciprofloxacin were Acinetobacter baumannii-calcoacetius complex (33%), E. coli (50%), S. aureus (26.7%), S. epidermidis (61.3%), S. haemolyticus (58.3%) and Staphylococcus sp. (coagulase negative, 56.9%), (Table 12); all microorganisms had 100% sensitivity to doxycycline, ertapenem, and imipenem (Tables 15, 16, 17); the microorganisms resistant to levofloxacin were A. baumannii-calcoacetius complex (33.3%), S. aureus (26.7%), S. epidermidis (61.3%), S. haemolyticus (75%), and Staphylococcus sp. (coagulase negative, 57.1%), (Table 21); 100% of bacteria were sensitive to linezolid (22); the microorganisms resistant to oxacillin were S. aureus (13.3%), S. epidermidis (58.1%), S. haemolyticus (66.7%), S. hominis (100%) and Staphylococcus sp. (coagulase negative, 42%) (Table 23); 107 of 116 samples were resistant to penicillin: K. pneumoniae (100%), S. aureus (100%), S. capitis (100%), S. epidermidis (93.5%), S. haemolyticus (100%), S. hominis (100%), S. saprophyticus (100%), Staphylococcus sp. (coagulase negative, 92%), and viridans group Streptococcus sp. (33.3%) (Table 24).
Regarding the results of antibiograms performed for rifampicin, all samples were sensitive, with the exception of two samples of Staphylococcus sp. (coagulase negative, 4%) (Table 25); the microorganisms resistant to sulfamethoxazole-trimetroprim were A. baumannii-calcoacetius complex (100%), E. coli (50%), S. epidermidis (6.5%), S. haemolyticus (25%), and Staphylococcus sp. (coagulase negative, 14%) (Table 26).
The microorganisms resistant to tetracycline were S. aureus (26.7%), S. epidermidis (16.1%), S. haemolyticus (8.3%). and Staphylococcus sp. (coagulase negative, 10%) (Table 27).
All 115 bacterial samples taken to perform the vancomycin antibiogram demonstrated a sensitive profile (Table 28); those resistant to tobramycin were six samples of S. epidermidis (30%) and two samples of Staphylococcus sp. (coagulase negative, 6.9%); the remaining 65 samples taken for the antibiogram were sensitive to tobramycin (Table 29).
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