Non-typeable Haemophilus influenzae biofilm production and severity in lower respiratory tract infections in a tertiary hospital in Mexico

Abstract

Non-typeable Haemophilus influenzae (NTHi) is a common opportunistic bacterial pathogen that primarily infects the respiratory mucosa. This study was conducted to assess clinical and microbiological data related to disease severity in patients with lower respiratory tract infections caused by NTHi in a tertiary care hospital in Mexico. NTHi isolates were subjected to serotyping, antimicrobial susceptibility evaluationand analyses of β-lactamase production, genetic relatednessand biofilm formation. Clinical and demographic data were retrieved from patients' records. The mean age of the patients was 40.3 years; the majority (n=44, 72.1 %) were male. The main comorbidities were arterial hypertension (n=22, 36.1 %) and diabetes mellitus (n=17, 27.9 %). NTHi isolates (n=98) were recovered from tracheal aspirate (n=57, 58.2 %), sputum (n=26, 26.5 %)and bronchial aspirate (n=15, 15.3 %) specimens. Low resistance to cefotaxime (n=0, 0.0 %), rifampin (n=1, 1.1 %) and chloramphenicol (n=3, 3.2 %) and greater resistance to ampicillin (n=30, 32.3 %) and trimethoprim-sulfamethoxazole (n=49, 52.7 %) were detected. β-Lactamase production was found in 17 (17.3 %) isolates. Isolates displayed high genetic diversity, and only 10 (10.2 %) were found to be biofilm producers. The antimicrobial susceptibility patterns of biofilm-producing and non-producing isolates did not differ. Biofilm production was associated with prolonged hospital stay (P=0.05). Lower respiratory NTHi isolates from Mexico showed low antimicrobial resistance and weak biofilm production. Younger age was correlated with lower Acute Physiology and Chronic Health Evaluation II score (moderate, P=0.07; severe, P=0.03).

Non‐typeable Haemophilus influenzae purulent pericarditis in a healthy child

“…1 One of the virulence factors is NTHi biofilm production, which is resistant to immune effectors. 4,6 The biofilm produced in the present case was strongly adherent, according to the criteria (non-adherent, OD 595 nm ≤0.120; weakly adherent, OD 595 nm >0.120-0.240; and strongly adherent, OD 595 nm >0.240). Hence, a strong biofilm might be involved in NTHi pericarditis in healthy infants.…”

“…Non‐typeable Haemophilus influenzae can cause invasive disease and increased bacterial virulence due to the acquisition of virulence factors . One of the virulence factors is NTHi biofilm production, which is resistant to immune effectors . The biofilm produced in the present case was strongly adherent, according to the criteria (non‐adherent, OD 595 nm ≤0.120; weakly adherent, OD 595 nm >0.120–0.240; and strongly adherent, OD 595 nm >0.240).…”

“…As a premise, a strong biofilm is unusual. For example, strong biofilms were not identified in one study that assessed 103 NTHi isolates from patients with lower respiratory tract infections in Mexico . Remarkably, Puig et al .…”

“…For example, strong biofilms were not identified in one study that assessed 103 NTHi isolates from patients with lower respiratory tract infections in Mexico. 4 Remarkably, Puig et al found, in isolates from invasive disease, that isolates from non-bacteremic community-acquired pneumonia had the highest levels of biofilm formation. 6 This could be due to the fact that invasive isolates must cross tissue barriers before causing infection.…”

“…We confirmed the lack of the capsular gene bexB on polymerase chain reaction. 3 In addition, the strain isolated from the pericardial effusion on microtiter plate assay had a strong biofilm formation ability (optical density at 595 nm [OD 595 nm ], 0.840), 4 which is associated with the bacterial virulence. On multi-locus sequence typing (MLST; http://www.mlst.net/) using the nucleotide sequences of seven housekeeping genes (adk, atpG, frdB, fucK, mdh, pgi, and recA), 5 the strain isolated from the pericardial effusion had sequence type (ST)187.…”