Cytology of tracheobronchial and bronchoalveolar lavage in healthy Holteins calves during the first month of life

Benesi F.J., Wachholz L., Bertagnon H.G., Leal M.L.R., Mori E. & Fernandes W.R. 2012. [Cytology of tracheobronchial and bronchoalveolar lavage in healthy Holteins calves during the first month of life.] Citologia dos lavados traqueobronquico (LTB) e broncoalveolar (LBA) de bezerros holandeses sadios durante o primeiro mes de vida. Pesquisa Veterinaria Brasileira 32(3):267-270. Departamento de Clinica Medica, Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Sao Paulo, SP 05508-270, Brazil. E-mail: febencli@usp.br The neonatal calf is a critical moment for adaptation of the newborn to extra uterine life. The respiratory tract is functionally very demanded and often affected by disease, resulting in direct loss of their function and causing serious economic losses in livestock. The basic point to reduce these losses is appropriate clinical evaluation of neonates; but the diagnosis based solely in physical examination is very difficult to establish. The use of complementary analysis such cytology of the respiratory tract becomes an important diagnostic tool; however their findings must be standardized in the face of different techniques employed. This research studied the dynamics of the cellularity of the bronchoalveolar and tracheobronchial region obtained through lung lavage harvested by nasotracheal catheterization technique and tracheocenthesis respectively, during the first month of life of healthy calves. The tracheobronchial cytology was influenced by the time, showing decreased number of alveolar macrophages and greater number of neutrophils, possibly increased by local irritation caused by the technique, which was repeated sequentially, and/or through greater stimulation of inhaled microorganisms deposited in this region. In the bronchoalveolar region no variation in the cellular constituents in function of time was found. The results allowed the conclusion the cell population of the tracheobronchial region has changed over the week-old calves, possibly due to the technique used and/or to the normal region physiology, represented by higher magnitudes of neutrophils. Otherwise, the cells of the broncholaveolar region showed a stable behavior during the first month of life of newborn calves, presenting numerical predominance of alveolar macrophages. O período neonatal dos bezerros é um momento crítico para adaptação do recém-nascido à vida extra uterina e o sistema respiratório, um dos mais exigidos funcionalmente, é frequentemente afetado por enfermidades, redundando no prejuízo direto da sua função e acarretando perdas econômicas importantes na pecuária. O ponto básico para reduzir estas perdas, é representado pela adequada avaliação clínica dos neonatos, todavia o diagnóstico baseado exclusivamente no exame ísico é muito di ícil de ser estabelecido. O uso de exames complementares como a citologia do trato respiratório torna-se uma ferramenta diagnóstica importante nestes casos, porém faz-se necessário, padronizar seus achados frente às diferentes técnicas empregadas para a sua obtenção. Assim, o presente estudo propôs-se acompanhar as variações dos constituintes celulares da região traqueobrônquica e broncoalveolar obtidos por lavados respiratórios pelos métodos de traqueocentese e por colheita nasotraqueal respectivamente, durante o primeiro mês de vida de bezerros sadios. Observou-se alteração no quadro citológico ao longo do tempo, quando a região traqueobrônquica foi lavada, expresso por diminuição da porcentagem de macrófagos alveolares, com aumento de neutró ilos, possivelmente, por maior irritação local provocada pela técnica, que se repetiu sequencialmente e/ou por maior estimulo de microorganismos inalados depositados nesta região. Na região broncoalveolar, não encontraram- -se variações nos constituintes celulares em função do tempo. Os resultados permitiram a conclusão que a população celular da região traqueobrônquica modi icou-se ao longo das semanas de vida dos bezerros, possivelmente pela técnica empregada e/ou isiologia normal da região, sendo representadas por maiores magnitudes de neutró ilos. De modo diverso, na região broncolaveolar, as células evidenciaram um comportamento estável durante o primeiro mês de vida dos bezerros neonatos, apresentando predomínio numérico dos macrófagos alveolares.

Wheezing in infants: frequency, clinical characteristics and treatment

Objective: To estimate the frequency and describe the clinical characteristics and respective treatments of previous history of wheezing. Methods: Infants aged 6-23 months with upper respiratory tract complaints and reporting previous wheezing were followed-up retrospectively. Data were registered on a validated standardized form. Results: Out of 451 infants, 164 (36.4%; 95%CI: 31.9-41.0) had a report of prior history of wheezing, 148 (32.8%; 95%CI: 28.5-37.4) during the first year of life. The mean age at the first episode of wheezing was 5.3 +/- 3.9 months. Among those who had had their first episode before 12 months of age, 38.5% reported 3 to 6 episodes and 14.2% > 6 episodes. Mean age at first episode was lower for those with a >= 3 episodes in comparison with those with <= 2 episodes (3.2 +/- 2.7 vs. 5.7 +/- 2.5 months, p < 0.001). Conclusion: One third of the infants reported wheezing during the first year of life. The earlier the first episode occurs, the more frequently wheezing recurs.

In vivo hydroquinone exposure causes tracheal hyperresponsiveness due to TNF secretion by epithelial cells

Hydroquinone (HQ) is the main oxidative substance in cigarette smoke and a toxic product of benzene biotransformation. Although the respiratory tract is an inlet pathway of HQ exposure, its effect on airway muscle responsiveness has not been assessed. We thus investigated the effects of low dose in vivo HQ-exposure on tracheal responsiveness to a muscarinic receptor agonist. Male Swiss mice were exposed to aerosolised 5% ethanol/saline solution (HQ vehicle; control) or 0.04 ppm HQ (1 h/day for 5 days) and tracheal rings were collected 1 h after the last exposure. HQ exposure caused tracheal hyper-responsiveness to methacholine (MCh), which was abolished by mechanical removal of the epithelium. This hyperresponsiveness was not dependent on neutrophil infiltration, but on tumour necrosis factor (TNF) secretion by epithelial cells. This conclusion was based on the following data: (1) trachea from HQ-exposed mice presented a higher amount of TNF, which was abrogated following removal of the epithelium; (2) the trachea hyperresponsiveness and TNF levels were attenuated by in vivo chlorpromazine (CPZ) treatment, an inhibitor of TNF synthesis. The involvement of HQ-induced TNF secretion in trachea mast cell degranulation was also demonstrated by the partial reversion of tracheal hyperresponsiveness in sodium cromoglicate-treated animals, and the in vivo HQ-exposure-induced degranulation of trachea connective tissue and mucosal mast cells, which was reversed by CPZ treatment. Our data show that in vivo HQ exposure indirectly exacerbates the parasympathetic-induced contraction of airway smooth muscle cells, mediated by TNF secreted by tracheal epithelial cells, clearly showing the link between environmental HQ exposure and the reactivity of airways. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

Exercise Inhibits Allergic Lung Inflammation

Aerobic conditioning (AC) performed either during or after sensitization reduces allergic inflammation in mice; however, the effects of AC performed before and during allergic sensitization on airway inflammation are unknown. Mice were divided into Control, AC, OVA, and AC + OVA groups. Mice were trained in a treadmill followed by either ovalbumin (OVA) sensitization or saline administration. Peribronchial inflammation, OVA-specific IgE and IgG1 titers, the expression of Th1 and Th2 cytokines, and airway remodeling were evaluated, as well as the expression of Eotaxin, RANTES, ICAM-1, VCAM-1, TGF-beta and VEGF. Aerobic conditioning performed before and during allergic sensitization displayed an inhibitory effect on the OVA-induced migration of eosinophils and lymphocytes to the airways, a reduction of IgE and IgG1 titers and an inhibition of the expression of Th2 cytokines. The AC + OVA group also demonstrated reduced expression of ICAM-1, VCAM-1, RANTES, TGF-beta and VEGF, as well as decreased airway remodeling (p < 0.05). The effects of AC before and during the sensitization process inhibit allergic airway inflammation and reduce the production of Th2 cytokines and allergen-specific IgE and IgG1.

Association between particulate matter air pollution and monthly inhalation and nebulization procedures in Ribeirao Preto, Sao Paulo State, Brazil

The study was designed to investigate the impact of air pollution on monthly inhalation/nebulization procedures in Ribeirao Preto, Sao Paulo State, Brazil, from 2004 to 2010. To assess the relationship between the procedures and particulate matter (PM10) a Bayesian Poisson regression model was used, including a random factor that captured extra-Poisson variability between counts. Particulate matter was associated with the monthly number of inhalation/nebulization procedures, but the inclusion of covariates (temperature, precipitation, and season of the year) suggests a possible confounding effect. Although other studies have linked particulate matter to an increasing number of visits due to respiratory morbidity, the results of this study suggest that such associations should be interpreted with caution.

Streptococcus pneumoniae: susceptibility to penicillin and moxifloxacin

Objective: To determine the minimum inhibitory concentrations (MICs) of parenteral penicillin and moxifloxacin against Streptococcus pneumoniae strains isolated at a hospital center. Methods: In-vitro, prospective study involving 100 S. pneumoniae isolates collected from patients who had been treated, between October of 2008 and July of 2010, at the Hospital das Clinicas complex of the University of Sao Paulo School of Medicine, located in the city of Sao Paulo, Brazil. The isolates were obtained from respiratory tract cultures or blood samples unrelated to meningeal infections, and they were tested for penicillin and moxifloxacin susceptibility by E-test. The MIC category interpretations were based on updated standards. Results: All isolates were fully susceptible to parenteral penicillin (MIC <= 2 mu g/mL), and, consequently, they were also susceptible to amoxicillin, ampicillin, third/fourth generation cephalosporins, and ertapenem. Of the S. pneumoniae strains, 99% were also susceptible to moxifloxacin, and only one strain showed an MIC = 1.5 mu g/mL (intermediate). Conclusions: Our results showed high susceptibility rates to parenteral penicillin and moxifloxacin among S. pneumoniae isolates unrelated to meningitis, which differs from international reports. Reports on penicillin resistance should be based on updated breakpoints for non-meningitis isolates in order to guide the selection of an antimicrobial therapy and to improve the prediction of the clinical outcomes.

Phylodynamics and Dispersal of HRSV Entails Its Permanence in the General Population in between Yearly Outbreaks in Children

Background: Human respiratory syncytial virus (HRSV) is one of the major etiologic agents of respiratory tract infections among children worldwide. Methodology/Principal Findings: Here through a comprehensive analysis of the two major HRSV groups A and B (n = 1983) which comprise of several genotypes, we present a complex pattern of population dynamics of HRSV over a time period of 50 years (1956-2006). Circulation pattern of HRSV revealed a series of expansions and fluctuations of co-circulating lineages with a predominance of HRSVA. Positively selected amino acid substitutions of the G glycoprotein occurred upon population growth of GB3 with a 60-nucleotide insertion (GB3 Insert), while other genotypes acquired substitutions upon both population growth and decrease, thus possibly reflecting a role for immune selected epitopes in linkage to the traced substitution sites that may have important relevance for vaccine design. Analysis evidenced the co-circulation and predominance of distinct HRSV genotypes in Brazil and suggested a year-round presence of the virus. In Brazil, GA2 and GA5 were the main culprits of HRSV outbreaks until recently, when the GB3 Insert became highly prevalent. Using Bayesian methods, we determined the dispersal patterns of genotypes through several inferred migratory routes. Conclusions/Significance: Genotypes spread across continents and between neighboring areas. Crucially, genotypes also remained at any given region for extended periods, independent of seasonal outbreaks possibly maintained by re-infecting the general population.

Human bocavirus infection diagnosed serologically among children admitted to hospital with community-acquired pneumonia in a tropical region

Human bocavirus (HBoV) is a human virus associated with respiratory disease in children. Limited information is available on acute infection with HBoV among children admitted to hospital with community-acquired pneumonia in tropical regions and the current diagnosis is inadequate. The aims were to diagnose and describe acute HBoV infections among children hospitalized for community-acquired pneumonia. In Salvador, Brazil, 277 children with community-acquired pneumonia were prospectively enrolled. Paired serum samples were tested by IgG, IgM, and IgG-avidity enzyme immunoassays (EIAs) using recombinant HBoV VP2. HBoV DNA was detected in nasopharyngeal aspirates and serum by a quantitative polymerase-chain reaction (PCR). HBoV DNA was detected in nasopharyngeal aspirates of 62/268 (23%) children and 156/273 (57%) were seropositive. Acute primary HBoV infection was reliably diagnosed (bearing at least two acute markers: Positive IgM, a fourfold increase/conversion of IgG, low IgG avidity or viremia) in 21 (8%) of 273 patients, 90% of 20 had HBoV DNA in nasopharyngeal aspirates, 83% with a high DNA load. The median age of infection with HBoV was 16 months, range 5-36.Community-acquired pneumonia was confirmed radiographically in 85% of 20 patients with acute HBoV infection diagnosed serologically. HBoV DNA was found in nasopharyngeal aspirates of 42/246(17%) children without an acute primary HBoV infection and available nasopharyngeal aspirate. Four children with HBoV secondary immune responses were detected, lacking both IgM and viremia. HBoV infection was diagnosed accurately in children aged 5-36 months with community-acquired pneumonia confirmed radiographically. PCR of nasopharyngeal aspirates is not a reliable marker of acute HBoV infection. J. Med. Virol. 84:253-258, 2012. (C) 2011 Wiley Periodicals, Inc.

Association between particulate matter air pollution and monthly inhalation and nebulization procedures in Ribeirão Preto, São Paulo State, Brazil

The study was designed to investigate the impact of air pollution on monthly inhalation/nebulization procedures in Ribeirão Preto, São Paulo State, Brazil, from 2004 to 2010. To assess the relationship between the procedures and particulate matter (PM10) a Bayesian Poisson regression model was used, including a random factor that captured extra-Poisson variability between counts. Particulate matter was associated with the monthly number of inhalation/nebulization procedures, but the inclusion of covariates (temperature, precipitation, and season of the year) suggests a possible confounding effect. Although other studies have linked particulate matter to an increasing number of visits due to respiratory morbidity, the results of this study suggest that such associations should be interpreted with caution.

A poluição do ar e o sistema respiratório

A poluição atmosférica encontra-se presente nos mais diferentes cenários ao longo dos últimos 250 anos, desde que a Revolução Industrial acelerou o processo de emissão de poluentes que, até então, estava limitado ao uso doméstico de combustíveis vegetais e minerais e às emissões vulcânicas intermitentes. Hoje, aproximadamente 50% da população do planeta vivem em cidades e aglomerados urbanos e estão expostas a níveis progressivamente maiores de poluentes do ar. Este estudo é uma revisão não sistemática sobre os diferentes tipos e fontes de poluentes do ar e os efeitos respiratórios atribuídos à exposição a esses contaminantes. Podem ser creditados aos poluentes particulados e gasosos, emitidos por diferentes fontes, aumentos nos sintomas de doenças, na procura por atendimentos em serviços de emergência e no número de internações e de óbitos. Mais do que descompensar doenças pré-existentes, exposições crônicas têm ajudado a aumentar o número de casos novos de asma, de DPOC e de câncer de pulmão, tanto em áreas urbanas quanto em áreas rurais, fazendo com que os poluentes atmosféricos rivalizem com a fumaça do tabaco pelo papel de principal fator de risco para estas doenças. Na rotina de clínicos e pneumologistas, esperamos contribuir para consolidar a importância da investigação sobre a exposição aos poluentes do ar e o reconhecimento de que esse fator de risco merece ser levado em conta na adoção da melhor terapêutica para o controle das descompensações agudas das doenças respiratórias e para a sua manutenção entre as crises.

Study of two novel streptococcus pneumoniae operons: pilus islet 2 and the lantibiotic operon

Analysis of publicly available genomes of Streptococcus pneumoniae has led to the identification of a new genomic element resembling gram-positive pilus islets (PIs). Here, we demonstrate that this genomic region, herein referred to as PI-2 (containing the genes pitA, sipA, pitB, srtG1, and srtG2) codes for a novel functional pilus in pneumococcus. Therefore, there are two pilus islets identified so far in this pathogen (PI-1 and PI-2). Polymerization of the PI-2 pilus requires the backbone protein PitB as well as the sortase SrtG1 and the signal peptidase-like protein SipA. PI-2 is associated with serotypes 1, 2, 7F, 19A, and 19F, considered to be emerging in both industrialized and developing countries. Interestingly, strains belonging to clonal complex 271 (CC271) contain both PI-1 and PI-2, as revealed by genome analyses. In these strains both pili are surface exposed and independently assembled. Furthermore, in vitro experiments provide evidence that the pilus encoded by PI-2 of S. pneumoniae is involved in adherence. Thus, pneumococci encode at least two types of pili that may play a role in the initial host cell contact to the respiratory tract. In addition, the pilus proteins are potential antigens for inclusion in a new generation of pneumococcal vaccines. Adherence by pili could represent important factor in bacterial community formation, since it has been demonstrated that bacterial community formation plays an important role in pneumococcal otitis media. In vitro quantification of bacterial community formation by S. pneumoniae was performed in order to investigate the possible role of pneumococcal pili to form communities. By using different growth media we were not able to see clear association between pili and community formation. But our findings revealed that strains belonging to MLST clonal complex CC15 efficiently form bacterial communities in vitro in a glucose dependent manner. We compared the genome of forty-four pneumococcal isolates discovering four open reading frames specifically associated with CC15. These four genes are annotated as members of an operon responsible for the biosynthesis of a putative lanctibiotic peptide, described to be involved in bacterial community formation. Our experiments show that the lanctibiotic operon deletion affects glucose mediated community formation in CC 15 strain INV200. Moreover, since glucose consumption during bacterial growth produce an acidic environment, we tested bacterial community formation at different pH and we showed that the lanctibiotic operon deletion affected pH mediated community formation in CC 15 strain INV200. In conclusion, these data demonstrate that the putative lanctibiotic operon is associated with pneumococcal CC 15 strains in vitro bacterial community formation.

Entwicklung eines Tests zur Ablösung von Tierversuchen beim Nachweis von Pertussis-Toxin

Weltweit existiert keine zum Tierversuch alternative Methode, um adsorbierte Pertussis-Impfstoffe auf restliche Toxin-Aktivität hin zu untersuchen. Der im Europäischen Arzneibuch vorgeschriebene Tierversuch besitzt nach Erfahrungen der Industrie, internationaler Prüfbehörden sowie des Paul-Ehrlich-Institutes eine schlechte Aussagekraft. Er ist wenig standardisierbar und weist häufig ein zweifelhaftes Ergebnis auf, so dass Wiederholungen und damit einhergehend ein hoher Verbrauch an Versuchstieren unumgänglich sind. Enthält der Impfstoff Reste von nicht-inaktiviertem Pertussis-Toxin (PTx), muss mit schweren und schwersten Nebenwirkungen bei den Impflingen gerechnet werden. In dieser Arbeit wurde ein In vitro-Nachweis für aktives PTx entwickelt. rnAngeregt durch Publikationen, wonach Pertussis-Toxin humane Monozyten aktiviert, wurde zunächst versucht, diesen Effekt zum Toxin-Nachweis auszunutzen. Die vorliegende Arbeit zeigt jedoch eindeutig, dass Pertussis-Toxin selbst nicht zur Stimulation humaner Monozyten führt. Vielmehr konnte nachgewiesen werden, dass die Aktivierung dieser Immunzellen auf Kontaminationen durch Lipopolysaccharide zurückzuführen ist. Damit wurden die Aussagen in den oben erwähnten Veröffentlichungen widerlegt. Dieses Ergebnis wurde bereits zur Publikation eingereicht.rnNunmehr wurden verschiedene Ansätze zum Nachweis von Pertussis-Toxin entwickelt, welche seine enzymatischen Aktivitäten als NAD-Glycohydrolase und ADP-Ribosyltransferase ausnutzen. Zunächst wurde versucht, die Hydrolyse von NAD zu ADP-Ribose und Nicotinamid photometrisch nachzuweisen. Wegen unbefriedigender Sensitivität wurde dieses Verfahren zu einem fluorometrischen Nachweis weiterentwickelt. Verwendet wurde hier fluorogenes etheno-NAD, welches von Pertussis-Toxin als Substrat akzeptiert wird. Letzteres Prinzip ist zum In vitro-Nachweis von Pertussis-Toxin geeignet, wird jedoch durch das in Impfstoffen häufig verwendete Adsorbens Aluminiumhydroxid gestört. Deshalb wurde dieser Ansatz aufgegeben und ein neuer Weg verfolgt, welcher am Energiestoffwechsel von humanen Zellen ansetzt. Eine Konsequenz des Angriffs von Pertussis-Toxin auf seine Zielzellen im Respirationstrakt besteht – nach komplexen Reaktionen des Signaltransduktionsweges – im Absenken des ATP-Gehaltes. Als menschliche Surrogat-Zellen wurden frisch isolierte periphere mononukleäre Zellen (PBMCs) sowie die permanente Lymphozyten-Zelllinie Jurkat eingesetzt und deren ATP-Gehalt mittels Luziferin-Luziferase-Lumineszenz gemessen. Der Test wird nicht durch Lipopolysaccharid gestört und auch Aluminiumhydroxid übt erst nach mehreren Stunden Inkubation einen interferierenden Einfluss aus. Ebenso konnte aktives Pertussis-Toxin mit Hilfe kryokonservierter PBMCs detektiert werden, auch in orientierenden Versuchen mit komplexen Impfstoffen. Der Pertussis-ATP-Test kommt der In vivo-Situation in der Zelle sehr nahe, weil beide Untereinheiten des Toxins in einem Test überprüft werden. Demnach soll er Bestandteil einer geplanten internationalen Studie zu alternativen Pertussis-Toxin-Testungen sein.

Deposition and biokinetics of inhaled nanoparticles

Particle biokinetics is important in hazard identification and characterization of inhaled particles. Such studies intend to convert external to internal exposure or biologically effective dose, and may help to set limits in that way. Here we focus on the biokinetics of inhaled nanometer sized particles in comparison to micrometer sized ones.The presented approach ranges from inhaled particle deposition probability and retention in the respiratory tract to biokinetics and clearance of particles out of the respiratory tract. Particle transport into the blood circulation (translocation), towards secondary target organs and tissues (accumulation), and out of the body (clearance) is considered. The macroscopically assessed amount of particles in the respiratory tract and secondary target organs provides dose estimates for toxicological studies on the level of the whole organism. Complementary, microscopic analyses at the individual particle level provide detailed information about which cells and subcellular components are the target of inhaled particles. These studies contribute to shed light on mechanisms and modes of action eventually leading to adverse health effects by inhaled nanoparticles.We review current methods for macroscopic and microscopic analyses of particle deposition, retention and clearance. Existing macroscopic knowledge on particle biokinetics and microscopic views on particle organ interactions are discussed comparing nanometer and micrometer sized particles. We emphasize the importance for quantitative analyses and the use of particle doses derived from real world exposures.

Recent advances into understanding some aspects of the structure and function of mammalian and avian lungs

Recent findings are reported about certain aspects of the structure and function of the mammalian and avian lungs that include (a) the architecture of the air capillaries (ACs) and the blood capillaries (BCs); (b) the pulmonary blood capillary circulatory dynamics; (c) the adaptive molecular, cellular, biochemical, compositional, and developmental characteristics of the surfactant system; (d) the mechanisms of the translocation of fine and ultrafine particles across the airway epithelial barrier; and (e) the particle-cell interactions in the pulmonary airways. In the lung of the Muscovy duck Cairina moschata, at least, the ACs are rotund structures that are interconnected by narrow cylindrical sections, while the BCs comprise segments that are almost as long as they are wide. In contrast to the mammalian pulmonary BCs, which are highly compliant, those of birds practically behave like rigid tubes. Diving pressure has been a very powerful directional selection force that has influenced phenotypic changes in surfactant composition and function in lungs of marine mammals. After nanosized particulates are deposited on the respiratory tract of healthy human subjects, some reach organs such as the brain with potentially serious health implications. Finally, in the mammalian lung, dendritic cells of the pulmonary airways are powerful agents in engulfing deposited particles, and in birds, macrophages and erythrocytes are ardent phagocytizing cellular agents. The morphology of the lung that allows it to perform different functions-including gas exchange, ventilation of the lung by being compliant, defense, and secretion of important pharmacological factors-is reflected in its "compromise design."

Physiologic cold shock of Moraxella catarrhalis affects the expression of genes involved in the iron acquisition, serum resistance and immune evasion

Background Moraxella catarrhalis, a major nasopharyngeal pathogen of the human respiratory tract, is exposed to rapid downshifts of environmental temperature when humans breathe cold air. It was previously shown that the prevalence of pharyngeal colonization and respiratory tract infections caused by M. catarrhalis are greatest in winter. The aim of this study was to investigate how M. catarrhalis uses the physiologic exposure to cold air to upregulate pivotal survival systems in the pharynx that may contribute to M. catarrhalis virulence. Results A 26°C cold shock induces the expression of genes involved in transferrin and lactoferrin acquisition, and enhances binding of these proteins on the surface of M. catarrhalis. Exposure of M. catarrhalis to 26°C upregulates the expression of UspA2, a major outer membrane protein involved in serum resistance, leading to improved binding of vitronectin which neutralizes the lethal effect of human complement. In contrast, cold shock decreases the expression of Hemagglutinin, a major adhesin, which mediates B cell response, and reduces immunoglobulin D-binding on the surface of M. catarrhalis. Conclusion Cold shock of M. catarrhalis induces the expression of genes involved in iron acquisition, serum resistance and immune evasion. Thus, cold shock at a physiologically relevant temperature of 26°C induces in M. catarrhalis a complex of adaptive mechanisms that enables the bacterium to target their host cellular receptors or soluble effectors and may contribute to enhanced growth, colonization and virulence.