A Study of Unusual Pacemaker Infection by Mycobacterium Tuberculosis in Indian Patients

Background

The expanding clinical indications of cardiac rhythm management have led to an increased use of pacemaker implantation which is associated with increased incidence of pacemaker infections. Staphylococcus aureus and epidermidis account for the vast majority of pacemaker infections. Pacemaker infection due to Mycobacterium tuberculosis (M. tuberculosis) is very rare, only few cases having been reported till date.

Methods

We describe here a study of three patients of pacemaker pocket infection with M. tuberculosis.

Conclusion

The possibility of mycobacterial pacemaker infection should always be kept in mind in patients with delayed pacemaker infection.     

Molecular Identification of Nocardia Isolates from Clinical Samples and an Overview of Human Nocardiosis in Brazil

Background

Nocardia sp. causes a variety of clinical presentations. The incidence of nocardiosis varies geographically according to several factors, such as the prevalence of HIV infections, transplants, neoplastic and rheumatic diseases, as well as climate, socio-economic conditions and laboratory procedures for Nocardia detection and identification. In Brazil the paucity of clinical reports of Nocardia infections suggests that this genus may be underestimated as a cause of human diseases and/or either neglected or misidentified in laboratory specimens. Accurate identification of Nocardia species has become increasingly important for clinical and epidemiological investigations. In this study, seven clinical Nocardia isolates were identified by multilocus sequence analysis (MLSA) and their antimicrobial susceptibility was also determined. Most Nocardia isolates were associated to pulmonary disease.

Methodology/Principal Findings

The majority of Brazilian human isolates in cases reported in literature were identified as Nocardia sp. Molecular characterization was used for species identification of Nocardia nova, Nocardia cyriacigeorgica, Nocardia asiatica and Nocardia exalbida/gamkensis. Data indicated that molecular analysis provided a different Nocardia speciation than the initial biochemical identification for most Brazilian isolates. All Nocardia isolates showed susceptibility to trimethoprim-sulfamethoxazole, the antimicrobial of choice in the treatment nocardiosis. N. nova isolated from different clinical specimens from one patient showed identical antimicrobial susceptibility patterns and two distinct clones.

Conclusions/Significance

Although Brazil is the world''s fifth-largest country in terms of land mass and population, pulmonary, extrapulmonary and systemic forms of nocardiosis were reported in only 6 of the 26 Brazilian states from 1970 to 2013. A least 33.8% of these 46 cases of nocardiosis proved fatal. Interestingly, coinfection by two clones may occur in patients presenting nocardiosis. Nocardia infection may be more common throughout the Brazilian territory and in other developing tropical countries than is currently recognized and MLSA should be used more extensively as an effective method for Nocardia identification.     

Identification of Bacteriology and Risk Factor Analysis of Asymptomatic Bacterial Colonization in Pacemaker Replacement Patients

Background

Recent researches revealed that asymptomatic bacterial colonization on PMs might be ubiquitous and increase the risk of clinical PM infection. Early diagnosis of patients with asymptomatic bacterial colonization could provide opportunity for targeted preventive measures.

Objective

The present study explores the incidence of bacterial colonization of generator pockets in pacemaker replacement patients without signs of infection, and to analyze risk factors for asymptomatic bacterial colonization.

Methods

From June 2011 to December 2013, 118 patients underwent pacemaker replacement or upgrade. Identification of bacteria was carried out by bacterial culture and 16S rRNA sequencing. Clinical risk characteristics were analyzed.

Results

The total bacterial positive rate was 37.3% (44 cases), and the coagulase-negative Staphylococcus aureus detection rate was the highest. Twenty two (18.6%) patients had positive bacterial culture results, of which 50% had coagulase-negative staphylococcus. The bacterial DNA detection rate was 36.4 % (43 cases). Positive bacterial DNA results from pocket tissues and the surface of the devices were 22.0% and 29.7%, respectively. During follow-up (median, 27.0 months), three patients (6.8%, 3/44) became symptomatic with the same genus of microorganism, S. aureus (n=2) and S. epidermidis (n=1). Multivariable logistic regression analysis showed that history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency were independent risk factors for asymptomatic bacterial colonization.

Conclusion

There was a high incidence of asymptomatic bacterial colonization in pacemaker patients with independent risk factors. Bacterial culture combined genetic testing could improve the detection rate.     

Rare case of osteomyelitis of tibial shaft caused by <Emphasis Type="Italic">Nocardia cyriacigeorgica</Emphasis>

Nocardiosis is a rare infection caused by the aerobic actinomycete of the Nocardia genus. In most cases, nocardiosis manifests as a lung infection or a bone lesion. Due to the nonspecific and mild clinical manifestations of nocardiosis, the establishment of definite diagnosis can be difficult. When antibiotic therapy is incorrectly targeted, only the symptoms of the disease are suppressed. The mainstay in the treatment of Nocardia osteomyelitis has so far been the combined surgical debridement with long-term, initially intravenous, antibiotic administration. We present the successful conservative treatment of a nocardiosis osteomyelitis of the tibia caused by the Nocardia cyriacigeorgica species in an 81-year-old female patient that manifested itself as a secondary affection on top of a primary nocardiosis infection of the lung. From microbiological examination, N. cyriacigeorgica was discovered; the identification was made using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) with an identification score of 1.9. The sensitivity was evaluated using E test. Sensitivity to trimethoprim/sulfamethoxazole, amikacin, imipenem, and linezolid was demonstrated. The bacteria were shown to be resistant to ciprofloxacin. For treatment, trimethoprim/sulfamethoxazole was used due to the value of minimum inhibitory concentration, which was 0.25 mg/L. The initial dose of 960 mg of trimethoprim/sulfamethoxazole every 8 h was reduced to 960 mg every 12 h after 3 months. The total duration of treatment was 7.5 months. Under the established treatment, the bone and lung lesions healed. Nocardiosis of the long bone is considered a rare disease and its precise diagnosis has not yet been standardized. We used the MALDI-TOF MS method for the identification of the causal organism which is a fast and reliable method according to current world literature even when compared with the rRNA genetic sequencing reference method. Our case study presents a rare case of osteomyelitis of tibial shaft caused by N. cyriacigeorgica and its successful conservative treatment.     

Different Rifampicin Inactivation Mechanisms in Nocardia and Related Taxa

Mycolic acid-containing bacteria inactivate rifampicin in a variety of ways such as glucosylation, ribosylation, phosphorylation and decolorization. These inactivations were found to be a species-specific phenomena in Nocardia and related taxa. Gordona, Tsukamurella and fast-growing Mycobacterium modified rifampicin by ribosylation of the 23-OH group of the antibiotic. Such ribosylation was not observed in Rhodococcus and Corynebacterium, but phosphorylation of the 21-OH group of rifampicin was observed in one strain of Rhodococcus. Nocardia modified the antibiotic by glucosylation (23-OH group) and phosphorylation, but ribosylation was not observed.     

诺卡氏菌烈性噬菌体vB_Ncarnea_KYD1的分离纯化与基因组分析

【背景】诺卡氏菌是一种广泛分布的好氧放线菌,可在人体内引起局部或播散性感染,尤其是在免疫功能低下的个体中。诺卡氏菌感染在临床上较难鉴定,而且不断有新型诺卡氏菌种被发现。不同类型、不同地域的诺卡氏菌具有流行差异和抗生素敏感性差异,阻碍了适当治疗方式的选择。利用病灶处的宿主菌分离得到噬菌体来控制诺卡氏菌感染的这种方法在近年来受到了各界的关注。【目的】尝试从环境中分离出能够用于临床治疗的针对诺卡氏菌的烈性噬菌体,并研究其基因组学特征。【方法】利用双层平板法分离得到目标噬菌体,观察其噬菌斑形态,并对噬菌体进行分离纯化,在透射电镜下鉴定其特征。提取噬菌体DNA进行全基因组测序与注释,并与数据库内已知噬菌体基因组进行比较,同时构建系统进化树以进行遗传进化分析。【结果】本文以肉色诺卡氏菌为宿主,从环境样本中分离出一株烈性噬菌体vB_Ncarnea_KYD1,在双层平板上可形成直径<2 mm的透亮均匀的噬菌斑。基因组分析表明,vB_Ncarnea_KYD1DNA为环状,大小为66 621 bp,共发现102个蛋白质编码区(coding sequence,CDS)及一个tRNA-Ser编码序列。透射电镜观察与系统进化树综合分析可以确定,vB_Ncarnea_KYD1为长尾噬菌体科的一个新属。其在进化过程中经历了复杂的基因重组过程。暂未发现毒力因子相关基因与抗性基因,具备实用价值。【结论】从环境水体中分离出一株烈性肉色诺卡氏菌噬菌体vB_Ncarnea_KYD1,通过电镜观察与基因组分析可知,此株噬菌体为长尾噬菌体,基因组中暂未发现不利于临床应用的相关基因,是一株相对安全的烈性诺卡氏菌噬菌体。研究结果丰富了国内噬菌体资源库,并为后续诺卡氏菌感染疾病的治疗提供支持。     

The infected or exposed breast implant: management and treatment strategies

Among the potential complications associated with the use of breast implants are the risks of periprosthetic infection and device extrusion. There is little published information about the effective management of these situations. Conservative recommendations include antibiotic therapy and removal of the implant until resolution of the infection or until the wound has healed. A retrospective review identified patients with periprosthetic infection or threatened or actual device exposure treated by the senior author. Twenty-four patients encompassing 26 affected prostheses were available for review and were classified into seven groups based on initial presentation as follows: group 1, mild infection (n = 8); group 2, severe infection (n = 4); group 3, threatened exposure without infection (n = 3); group 4, threatened exposure with mild infection (n = 3); group 5, threatened exposure with severe infection (n = 1); group 6, actual exposure without clinical infection (n = 5); and group 7, actual exposure with infection (n = 2). To salvage the prosthesis in these patients, various treatment strategies were utilized. All patients with a suspected infection or device exposure were started immediately on appropriate antibiotic therapy (oral antibiotics for mild infections and parenteral antibiotics for severe infections). Salvage methods included one or more of the following: antibiotic therapy, débridement, curettage, pulse lavage, capsulectomy, device exchange, primary closure, and/or flap coverage. Twenty (76.9 percent) of 26 threatened implants with infection or threatened or actual prosthesis exposure were salvaged after aggressive intervention. The presence of severe infection adversely affected the salvage rate in this series. A statistically significant difference exists among those patients without infection or with mild infection only (groups 1, 3, 4, and 6); successful salvage was achieved in 18 (94.7 percent) of 19 patients, whereas only two of seven of those implants with severe infection (groups 2, 5, and 7) were salvaged (p = 0.0017). Ten (90.9 percent) of 11 devices with threatened or actual exposure, not complicated by severe infection (groups 3, 4, and 6), were salvaged. Several treatment strategies were developed for periprosthetic infection and for threatened or actual implant exposure. Patients with infection were placed on oral or intravenous antibiotics; those who responded completely required no further treatment. For persistent mild infection or threatened or actual exposure, operative intervention was required, including some or all of the following steps: implant removal, pocket curettage, partial or total capsulectomy, débridement, site change, placement of a new implant, and/or flap coverage; the menu of options varied with the precise circumstances. No immediate salvage was attempted in five cases, due to either severe infection, nonresponding infection with gross purulence, marginal tissues, or lack of options for healthy tissue coverage. Based on the authors' experience, salvage attempts for periprosthetic infection and prosthesis exposure may be successful, except in cases of overwhelming infection or deficient soft-tissue coverage. Although an attempt at implant salvage may be offered to a patient, device removal and delayed reinsertion will always remain a more conservative and predictable option.     

Pulmonary nocardiosis associated with cerebral abscess successfully treated by co-trimoxazole: a case report

Nocardiosis is an acute or chronic infectious disease caused by the soil-borne filamentous bacteria belonging to the genus Nocardia. The organisms opportunistically infect both immunocompromised and immunocompetent individuals. The lungs are the primary site of infection and brain abscess is, by far, the most common complication following nocardial metastasis from pulmonary lesions. Although surgical intervention must always be considered in the treatment of nocardial brain abscess, it can obviously be cured by antibiotic therapy alone. This report describes a case infected by Nocardia cyriacigeorgica. Identification of the infectious agent was achieved by conventional and semi-nested PCR techniques. A 55-year-old woman with fever was referred to the infect disclinic of Imam Khomeini hospital in Tehran and was hospitalized after clinical assessment. She was a kidney transplant recipient for 4 years and was taking immunosuppressive treatment including azathioprine and methylprednisolone. Follow-up of the patient by CT scan revealed pulmonary infection and cerebral lesions. Specimens of the brain lesions contained filamentous bacteria. The patient received a combination of co-trimoxazole and ceftriaxone and brain abscesses as well as lung inflammation disappeared gradually during the course of antibiotic therapy within 3 months. The patient was discharged from the hospital after 2 months of therapy.     

Characteristics of cardiac device infections in the Isala Hospital; a large volume tertiary care cardiology centre

Aims

To determine the frequency, characteristics and risk factors of cardiac device infections in the Isala Hospital.

Methods

We retrospectively studied all patients who underwent cardiac device procedures performed in the cardiac catheterisation lab and the operating room from 2010 to 2012. All patients who developed a cardiac device infection were reviewed for its characteristics.

Results

31/2026 patients developed a cardiac device infection (1.5 %). One (3.2 %) patient died within 30 days of hospitalisation. Device infection rates for procedures in the catheterisation lab and operating room were similar (p = 0.60). Positive cultures were present in 27/31 (87 %) cases. These consisted predominantly of micro-organisms that are part of the skin flora (84 %). The mean time between device procedure and infection was 14 ± 21 months (range 0–79). Cardiac device infection was significantly associated with device revision, (65 % were revisions in patients with device infection vs. 30 % revisions in patients without device infection, p = 0.011) and placement of a left ventricular lead in pacemaker implantations (59 % of patients with vs. 51 % of patients without device infection, p < 0.001).

Conclusion

The frequency of cardiac device infection was 1.5 % with a mortality of 3.2 % within 30 days, which is lower compared with other registries. Cardiac device infections were associated with device revisions and placement of left ventricular leads in pacemaker implantations.     

Identification and Characterization of Non-Tuberculous Mycobacteria Isolated from Tuberculosis Suspects in Southern-Central China

The incidence of non-tuberculous mycobacteria (NTM)-related death has increased globally recently. To obtain information of the species and characterization of pathogens involved in NTM pulmonary infection in Southern-central China, we identified 160 non-tuberculous infection cases from 3995 acid-fast bacilli (AFB)-positive tuberculous suspects. We then randomly selected 101 non-tuberculous patients, isolated bacteria from their sputa and genotyped the pathogens using the 16S rRNA gene and 16S-23S rRNA internal transcribed spacer sequences. M. intracellulare (32.67%, 33/101), M. abscessus (32.67%, 33/101) and M. fortuitum (7.92%, 8/101) are identified in these isolates. Surprisingly, non-mycobacteria including Gordonia (8.91%, 9/101), Nocardia (5.94%, 6/101) and Tsukamurella (0.99%, 1/101) are also discovered, and the case of Tsukamurella pulmonis infection is first discovered in Southern-central China. Moreover, species of M. mucogenicum group, M. chubuense, M. kansasii, M. gastri, M. avium, M. porcinum and M. smegmatis are identified. In addition, nine immune compromised cases (8.91%, 9/101), including type two diabetes mellitus and HIV/AIDS are found to be infected with non-tuberculous bacteria. This study revealed the distribution and characteristics of non-tuberculous AFB pathogen infection occurred in Southern-central China, and suggested that physicians should be alert of the emerging of NTM and non-mycobacteria infection in AFB positive cases and take caution when choosing chemotherapy for tuberculosis-like pulmonary infections. Generally, this study may help with the development of new strategy for the diagnosis and treatment of mycobacterial infection.     

Extraction Of Transvenous ICD Leads In An Over-ninety Years Old Patient

There is a general consensus that once a part of an implanted cardiac device becomes infected, it is usually impossible to cure the infection without completely removing all prosthetic material from the body. Consequently the Heart Rhythm Society (HRS) included the pocket infection or erosion as a class I indication for pacemaker lead exctraction. However, the procedure still carries a high risk of life-threatening complications due to fibrotic attachments between leads, veins, valves or other endocardial structures, notwithstanding specific tools and techniques that have been developed to assist the lead removal, preventing tissue laceration.     

Phospholipid and acid composition of Nocardia and nocardoid bacteria as criteria of classification

Phospholipid and acid composition of 5 strains of ‘true’ Nocardia and 4 strains of nocardoid bacteria have been studied. A great homogeneity was found in all the Nocardia species: phospholipids consist of cardiolipin, phosphatidyl ethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. Streptomyces (Nocardia) mediterranei did not contain phosphatidylinositol and Oerskovia (Nocardia) turbata had no phosphatidyl ethanolamine. The fatty acid composition of these phospholipids was determined and was found different in Nocardia and nocardoid species. Nocardia were rich in straight chain fatty acids and tuberculostearic acid while the phospholipids of nocardoid bacteria contained greater amounts of branched fatty acids. The fatty acids from acetone soluble lipids consisted of hydroxy and non-hydroxy compounds. Hydroxy acids were found in Nocardia which contained nocardic acids: high MW β-hydroxy α-branched acids and in S. mediterranei which contained β-hydroxy acids with 15–17 carbon atoms. Non-hydroxy acids were essentially palmitic and tuberculostearic acids in Nocardia species while S. mediterranei and O. turbata contained great amounts of iso acids from C₁₄ to C₁₇. Phospholipid and acid composition are discussed as criteria of taxonomic classification of Nocardia and related Actinomycetes.     

Echinococcosis: An Economic Evaluation of a Veterinary Public Health Intervention in Rural Canada

Echinococcosis is a rare but endemic condition in people in Canada, caused by a zoonotic cestode for which the source of human infection is ingestion of parasite eggs shed by canids. The objectives of this study were to identify risk factors associated with infection and to measure the cost-utility of introducing an echinococcosis prevention program in a rural area. We analyzed human case reports submitted to the Canadian Institutes for Health Information between 2002 and 2011. Over this 10 year period, there were 48 cases associated with E. granulosus/E. canadensis, 16 with E. multilocularis, and 251 cases of echinococcosis for which species was not identified (total 315 cases). Nationally, annual incidence of echinococcosis was 0.14 cases per 100 000 people, which is likely an underestimate due to under-diagnosis and under-reporting. Risk factors for echinococcosis included female gender, age (>65 years), and residing in one of the northern territories (Nunavut, Yukon, or Northwest Territories). The average cost of treating a case of cystic echinococcosis in Canada was $8,842 CAD. Cost-utility analysis revealed that dosing dogs with praziquantel (a cestocide) at six week intervals to control cystic echinococcosis is not currently cost-effective at a threshold of $20,000-100,000 per Quality Adjusted Life Year (QALY) gained, even in a health region with the highest incidence rate in Canada ($666,978 -755,051 per QALY gained). However, threshold analysis demonstrated that the program may become cost-saving at an echinococcosis incidence of 13-85 cases per 100,000 people and therefore, even one additional CE case in a community of 9000 people could result in the monetary benefits of the program outweighing costs.     

Halo-shape technique for leadless pacemaker implantations: A case report

A 92-year-old woman underwent an implantation of a leadless pacemaker (Micra; Medtronic, Inc, Minneapolis, MN) for complete atrioventricular block after a transvenous lead extraction due to a pocket infection of a dual chamber pacemaker. Marked scoliosis and a humpback due to an advanced age made it impossible to direct the tip of the pacemaker delivery catheter towards the right ventricular septum or apex and shape the catheter into a gooseneck-shape. Thus, by attaining a halo-catheter shape of the delivery catheter, the catheter tip could be directed toward the infero-basal portion of the right ventricular septum. The pacemaker was successfully deployed at that site without any complications, and good device parameters were achieved. The halo-shape technique may be also an alternative method for delivering a leadless pacemaker in patients with an unsuccessful delivery of a leadless pacemaker to the right ventricular septum using the conventional gooseneck-shape technique.     

Gonorrhoea and the Intrauterine Contraceptive Device

Though pelvic infection in women fitted with an intrauterine device (I.U.C.D.) is reported to be rare, three cases, gonococcal in origin, are presented. These case histories suggest that the presence of an I.U.C.D. increases the severity of gonorrhoea, while removal of the device before antibiotic therapy is probably essential for proper management. The literature and our experience suggest that where pelvic infection and an I.U.C.D. coexist gonorrhoea should be considered a likely diagnosis.     

A genome sequence-based approach to taxonomy of the genus Nocardia

The genus Nocardia includes both pathogens and producers of useful secondary metabolites. Although 16S rRNA analysis is required to accurately discriminate among phylogenetic relationships of the Nocardia species, most branches of 16S rRNA-based phylogenetic trees are not reliable. In this study, we performed in silico analyses of the genome sequences of Nocardia species in order to understand their diversity and classification for their identification and applications. Draft genome sequences of 26 Nocardia strains were determined. Phylogenetic trees were prepared on the basis of multilocus sequence analysis of the concatenated sequences of 12 genes (atpD-dnaJ-groL1-groL2-gyrB-recA-rpoA-secA-secY-sodA-trpB-ychF) and a bidirectional best hit. To elucidate the evolutionary relationships of these genes, the genome-to-genome distance was investigated on the basis of the average nucleotide identity, DNA maximal unique matches index, and genome-to-genome distance calculator. The topologies of all phylogenetic trees were found to be essentially similar to each other. Furthermore, whole genome-derived and multiple gene-derived relationships were found to be suitable for extensive intra-genus assessment of the genus Nocardia.     

Insights from the comparative genome analysis of natural rubber degrading Nocardia species

Nocardia are known to be a facultative human pathogen and can cause infection in immune compromised patients. Though the details research on the virulence factors of Nocardia are scanty but numerous genes that code such factors were reported from different species of Nocardia. Despite of the presence of several virulence factors, species of this genus have been shown to have role in remediation of many toxic and hazardous materials from the environment. In this study, genome sequences of rubber degrading Nocardia sp. BSTN01 and N.nova SH22a have been analyzed to locate the potential virulence genes. Also, the genomes of facultative pathogenic Nocardia like, N.africana, N. brasiliensis, N. kruczakiae, N. transvalensis and N. veterana have been analyzed to find the gene encoding latex clearing protein (Lcp), a rubber oxygenase enzyme of Gram-positive action bacteria. The study provides an insight about the potentiality of rubberdegrading Nocardia species to emerge as future human pathogens and also the probability of a serious concern if the studied facultative pathogens of Nocardia like N. africana, N. brasiliensis, N. kruczakiae, N. transvalensis and N. veterana are capable of degrading rubber, a regularly used material in clinics. Moreover, use of such possible pathogenic strains for their known role in bioremediation of rubber waste from the environment might be deleterious.     

Changing pattern of antibiotic susceptibility in intensive care units: ten years experience of a university hospital

The study was performed to assess microorganisms and antibiotic susceptibility patterns during ten years in intensive care units of a University Hospital. Infection Control Committee has active, prospective surveillance in ICUs for thirteen years. Ten years data of ICUs was evaluated retrospectively from surveillance forms. Microorganisms and their antibiotic resistance were recorded according to the years. During ten years, gram negative microorganisms were the most frequent isolated microorganisms from clinical specimens. Acinetobacter baumannii (21.8%), Pseudomonas aerigunosa (16%), Escherichia coli (10.4%) and Klebsiella pneumoniae (8%) were the most common gram negative microorganisms. However, Staphylococcus aureus was the most prevalent gram positive microorganism, the incidence decreased from 18.6% to 4.8% during ten years. Also antibiotic susceptibility of microorganisms changed during ten years. Carbapenem resistance increased from 44% to 92% in A. baumannii and ciprofloxacin resistance increased in E. coli from 28% to 60% and in K. pneumoniae from 21% to 55% during ten years. However, methicilin resistance decreased in S. aureus from 96% to 54%. In conclusion, antibiotic resistance is growing problem in ICUs. Rationale antibiotic policies and infection control measures will prevent the development of resistance.     

Defending against parasites: fungus-growing ants combine specialized behaviours and microbial symbionts to protect their fungus gardens

Parasites influence host biology and population structure, and thus shape the evolution of their hosts. Parasites often accelerate the evolution of host defences, including direct defences such as evasion and sanitation and indirect defences such as the management of beneficial microbes that aid in the suppression or removal of pathogens. Fungus-growing ants are doubly burdened by parasites, needing to protect their crops as well as themselves from infection. We show that parasite removal from fungus gardens is more complex than previously realized. In response to infection of their fungal gardens by a specialized virulent parasite, ants gather and compress parasitic spores and hyphae in their infrabuccal pockets, then deposit the resulting pellet in piles near their gardens. We reveal that the ants' infrabuccal pocket functions as a specialized sterilization device, killing spores of the garden parasite Escovopsis. This is apparently achieved through a symbiotic association with actinomycetous bacteria in the infrabuccal pocket that produce antibiotics which inhibit Escovopsis. The use of the infrabuccal pocket as a receptacle to sequester Escovopsis, and as a location for antibiotic administration by the ants' bacterial mutualist, illustrates how the combination of behaviour and microbial symbionts can be a successful defence strategy for hosts.