Mixed Infection

Mixed Infection, diseases caused not by one, but by several types of microorganisms; if one infection follows another, it is called a secondary infection. For practical purposes, secondary infections can be included in the group of mixed infections. The number of individual types of mixed infections is extremely large, but only the most frequently occurring forms have practical significance. The number of diseases in individual forms of mixed infection is related to the properties of the microorganisms that make up the pathogens, to the characteristics of the affected macroorganism, to socio-domestic conditions, and to the epidemic state of the given locality. The infection of the body simultaneously and sequentially by different microorganisms, depending on their characteristics, either does not change their virulence or, conversely, can significantly bring about changes in both directions of enhancement and weakening (see Infection and Combinations of Diseases). Unfortunately, combinations that result in the weakening of the virulence of the pathogens involved are few (malaria and progressive paralysis, relapsing fever and progressive paralysis). More often, the combination of pathogens does not change their virulence or increases it (diphtheria and streptococcal infection, influenza and scarlet fever, measles and tbc, whooping cough and tbc, etc.).- Among the characteristics of the macroorganism that influence the incidence of various forms of mixed infection, age, constitution, and the presence of pathological states play the greatest role. Age and constitutional factors manifest their influence in mixed childhood infections (the largest number of combinations of measles with scarlet fever falls on children of younger age groups, etc.). The presence of pathological states affects not only the number of childhood mixed infections but also the appearance and growth of other forms of mixed infection (N-parabacillosis and relapsing fever in exhaustion). Socio-domestic conditions among the factors determining the magnitude of mixed infections should be given an important place, especially the size and nature of contact (see Hospital-acquired infections). This also applies to polyclinic-type institutions. The epidemiological significance of mixed infections in terms of increasing the incidence of individual types of infections is manifested in the fact that in a number of cases, due to diagnostic difficulties, the identification of individual components of the disease forms either does not occur at all or occurs with great delay, which of course can contribute to the spread of infection. Prevention of mixed infections is based mainly on the general principles for combating acute infectious diseases, and it is especially important to identify the group having the greatest practical significance, namely the group of childhood mixed infections. Prevention of mixed infections in children's hospitals should generally be carried out by means of measures to combat hospital-acquired infections (see) with only certain additions of special measures. In combating the diphtheria component of mixed infections on a large scale based on a consistent plan, the method of passive immunization should be used. In measles departments with wards for a large number of patients, when it is not possible to place patients in small rooms, it is necessary to resort to mass immunization with sequential administrations every 5-6 days in minimal amounts (0.1) of antidiphtheric serum; such bridges are created to maintain the body in a desensitized state in relation to horse serum protein. The state of desensitization must be maintained due to the possible need for repeated administration of serum, as passive immunization of measles patients does not completely protect against diphtheria for 2-3 week periods. In scarlet fever departments, in addition to the administration of antidiphtheric serum to all detected diphtheria bacillus carriers, it is necessary for the timely detection of mild forms of diphtheria and simply bacillus carriers to perform bacteriological studies not only upon admission of the patient and in cases of suspicion of diphtheria, but also after the acute manifestations from the throat have subsided. Discharge from scarlet fever departments of children in whom carriage of diphtheria sticks has been detected should be carried out with certain precautions (accounting for the environment of the discharged person, notification of sanitary supervision, absolute absence of clinical manifestations, accounting for the duration of carriage). In combating the scarlet fever component in mixed infections in diphtheria departments, it is desirable to isolate (separate) all patients with clinically unclear forms in terms of diagnosis. At least partial isolation is also required for patients who give serum sickness. Prevention of internal infections with mixed infections in children's consultations and polyclinics is based mainly on the proper organization of these institutions and on the organization of filters and airlocks in them (see Hospital). Individual forms of mixed infection. Combination of scarlet fever with other infectious diseases. Scarlet fever and diphtheria. This form is common, which is partly related to the mutual increase in predisposition of scarlet fever and diphtheria to each other. Diphtheria can occur simultaneously with scarlet fever, can join at different stages of the scarlet fever disease, and can precede scarlet fever. The most severe forms occur when both diseases occur simultaneously. In addition to the selective action of diphtheria toxin on the cardiovascular system, the severity is caused by the development of streptococcal-type scarlet fever complications (extensive necrosis, neck phlegmon, etc.), which often lead the patient to a septicopyemic state. When scarlet fever and diphtheria occur simultaneously, characteristic dense white plaques characteristic of diphtheria may be present on the tonsils, tongue, arches, and posterior pharyngeal wall. But in some cases, the clinical picture is not characteristic, and only necrotic damage to the throat or lacunar angina is observed, and sometimes only a catarrhal condition of the throat is noted. Later, in such cases, the plaques may spread to neighboring parts of the throat. In rare cases, the process spreads to the larynx and causes a picture of croup. Paralysis of the muscles of the soft palate, eye muscles, limb muscles, etc. are not common. The presence of a diphtheria component is established by the picture of the throat (dense white, spreading plaques), by the characteristic odor from the mouth, by subsequent changes (spread of plaques, characteristic of their reverse development, involvement of the larynx in the process), by complications (paralysis, diphtheric nature of damage to the cardiovascular system). The bacteriological method of diagnosis has exceptionally great importance, especially in diagnosing clinically atypical cases. Unfortunately, this method itself does not always give an answer to doubts regarding the diagnosis. In some cases, and more often when scarlet fever and diphtheria occur simultaneously in the acute stages, bacilli cannot be found (suppression of diphtheria flora). On the other hand, positive findings themselves do not yet indicate the presence of diphtheria disease, since among patients with scarlet fever there may be simply diphtheria bacillus carriers (according to Shlosman, such carriers among scarlet fever patients are about 6%, according to Pochinkova-14.2%). Despite the noted reservations, the importance of bacteriological analysis for diagnosing the diphtheria component in mixed infection-scarlet fever and diphtheria-should be recognized as extremely great. Cases of the addition of diphtheria disease to scarlet fever in the stage of convalescence are also common. The course of these cases is not uniform. Severe forms can be encountered, but mild forms are also common. In this case, the picture of diphtheria damage can be typical with characteristic plaques, in rare cases with the spread of the process to the larynx. Often, diphtheria disease occurs in the form of rhinitis (purulent or bloody-purulent discharge, crusts, excoriations on the nasal mucosa, etc.). When the throat is affected, atypical forms in the form of follicular-lacunar anginas or further in the form of catarrhal angina also occur. Severe forms, especially forms with laryngeal involvement, have a poor prognosis. Antidiphtheric serum in some severe cases, despite its correct use, does not give a complete effect. In diagnosing these forms, the bacteriological method should also be given exceptionally great importance, and since it is sometimes difficult to draw the line between clinical diphtheria and bacillus carriage, in order to establish the diagnosis, it is necessary to resort, in addition to clinical analysis, to refined bacteriological analysis (quantitative analysis, etc.). Scarlet fever, in turn, often joins diphtheria. The superposition of scarlet fever on diphtheria disease, in addition to the mutual predisposition of these infections, also partly depends on the sensitization of the body due to the mass administration of serum to diphtheria patients. It is precisely during serum sickness that scarlet fever often joins diphtheria.

Scarlet fever, superimposed on diphtheria, can even in the stage of convalescence proceed severely with complications in the form of widespread necrosis of the pharynx and nasopharynx, purulent lymphadenitis, phlegmon of the neck, otitis, mastoiditis. In such cases, septicopyemic conditions can also occur, leading to the death of patients. In some cases, scarlet fever that has joined diphtheria does not proceed severely. The diagnosis of superimposed scarlet fever as a rule does not present particularly great difficulties. Difficulties sometimes arise when scarlet fever joins diphtheria at the moment of serum disease. Here, one has to pay special attention to the condition of the pharynx and to the fine-pointed rash, which sometimes appears only on individual areas next to the rash characteristic of serum disease. In some cases, it is necessary to resort to additional methods: research (bacteriological research, rash fading reaction, blood research, etc.). Scarlet fever and measles. The combination of scarlet fever and measles also occurs frequently. These forms give high mortality, especially among children of younger age groups. The worst prognosis is given in cases of approximately simultaneous course of both disease forms. But the joining of one infection to another, even in the stage of remote convalescence, worsens the prognosis, and in the latter cases, a normal course of both infections can occur. The high mortality in the combination of scarlet fever and measles is due to the development of a large number of scarlet fever complications in the form of necroses, purulent lymphadenitis, otitis, mastoiditis, and on the other hand, is connected with the increase in the number and severity of complications characteristic of measles, mainly in the form of pneumonias complicated by abscesses and empyemas. The noted complications of a scarlet fever nature often develop at late, atypical times, and the measles infection causes a severe wave of septic complications not only when joining a severe form of scarlet fever, but also a mild one. At present, due to the widespread seroprophylaxis of measles, and also partly because seroprophylaxis of measles in scarlet fever patients often does not lead to complete prevention of the disease, but only to its mitigation, combinations of scarlet fever with measles occur in children who have undergone seroprophylaxis. The course of such combinations is favorable, fatal outcomes in them are the exception and occur only when measles joins severe scarlet fever and moreover in children who received an insufficient amount of human serum. Nevertheless, provocation of streptococcal complications, as well as an increased tendency to pulmonary complications in individual cases can also occur in these combinations. The diagnosis of cases where one infection joins another in the stage of convalescence does not present great difficulties, but when both diseases occur simultaneously and especially when the measles and scarlet fever rashes appear simultaneously, diagnosis in a number of cases becomes difficult. These difficulties occur precisely in those cases when the symptoms having diagnostic significance are absent or lose their characteristic expression (condition of the pharynx, condition of the skin cover, etc.). In such cases, the rash on only certain parts (characteristic of scarlet fever rash) is fine-pointed; on the other hand, the measles rash at this time may not be completely similar to the normally occurring one. After an extended prodrome (sometimes accompanied by a prodromal spotted rash), the rash first appears only in the form of small red spots corresponding to swollen skin follicles (in places corresponding to the location of the measles rash), and then the eruption in the form of large raised spots quickly progresses and moreover also mainly in places characteristic of the measles rash. In some places, the measles rash can have an urticarial character. Subsequently, the measles rash quickly disappears, and against the background of pigmentation, the scarlet fever rash may remain, often appearing in a more distinct form. In the further course of the disease, the diagnosis is very often confirmed by the characteristic development of symptoms and the appearance of typical complications (pigmentation, peeling, lymphadenitis, necroses, etc.). For timely diagnosis, additional research methods can be used (rash fading reaction, blood research, diazo reaction, etc.). When analyzing all data and comparing them, data of an anamnestic nature should not be ignored, both in relation to the clinic and epidemiology. Combination of scarlet fever and chickenpox. This form is not uncommon, and scarlet fever sometimes joins chickenpox in such a way that the site of infection entry is a scratched element of the rash (extrabuccal scarlet fever). When chickenpox joins scarlet fever, there are also cases of severe course of chickenpox with deep necrosis at the site of pustules. In turn, chickenpox provokes the appearance of hemorrhagic nephritis. Scarlet fever can combine with a whole range of other infectious forms (typhus abdom., paratyphus, typhus exanth., meningitis cerebro-spin., etc.). With almost all these combinations, especially if they occur simultaneously, a worsening of the course of the disease is noted. A certain relative exception is the combination of scarlet fever with tuberculosis infection. Indeed, in scarlet fever patients, an exacerbation of tuberculosis and its generalization can occur, but such cases, in contrast to what is observed with the combination of tuberculosis with measles, influenza, whooping cough, are not often observed, rather as an exception. Combination of measles with other acute infectious diseases. Combination of measles and diphtheria. Measles patients are strongly predisposed to diphtheria infection. This predisposition and the associated increased incidence of diphtheria in measles patients occur not only in the acute stage of measles, but also in the stage of convalescence. In contrast to scarlet fever, in measles, diphtheria of the larynx is observed extremely frequently. These cases of diphtheria localization are especially common in small children. Furthermore, a common form is rhinitis, with the secretion of mucopurulent and purulent-bloody fluid or simply with crusts and excoriations on the nasal mucosa. Diphtheria of the pharynx proceeds either typically with characteristic plaques or in the form of vulgar angina. The bacteriological method is of great help in the diagnosis of such cases. The diagnosis of diphtheric laryngitis and croup in measles patients is difficult. In general, one must remember that measles croup is most often diphtheritic, and even with negative results (more accurately before receiving the answer), it is necessary to administer antitoxin serum to these patients. Diphtheria of the larynx in measles children is an extremely severe disease, often leading to the death of the child, and the spread of the process occurs with great rapidity, and intubation and tracheotomy are very poorly tolerated by such patients (about 100% mortality). Combination of measles and whooping cough is also unfavorable. When measles joins whooping cough, especially in small children, there may be insufficient development of the measles rash or its rapid disappearance with a simultaneously rapidly developing picture of capillary bronchitis, which often leads to the death of the child. When whooping cough joins measles, the process from the respiratory tract takes a prolonged course for many weeks and even months, which in turn leads to the development of chronic indurative changes, accompanied by the formation of bronchiectasis, feverish condition, and severe emaciation. Combination of measles and other infections gives a severe course in relation to both components. Influenza in combination with childhood infections significantly changes the course of the latter and increases mortality. Leaving aside the question of the etiological nature of influenza (see), it is necessary to note the extremely important significance of combinations of childhood infections with pneumococcal and Pfeiffer's infections. The morphological expression of these combinations is usually lesions of the respiratory organs and in particular pneumonia. These infections play a major role in the pathology and mortality not only of measles and whooping cough, but also of diphtheria and scarlet fever (especially in the group of small children). Mortality from scarlet fever due to pneumonia is on average determined in */ cases of all autopsy material (Hutinel). In the etiology of these pneumonias, the main role belongs to pneumococci and Pfeiffer's auxiliary bacilli. At the same time, Pfeiffer's bacilli are not only an epithelial necrotizing poison but also one of the factors increasing the virulence of streptococcus (Burgers). Possibly, the increase in both quantitative and qualitative streptococcal complications under the influence of the so-called influenza infection is also connected in some way with the noted property of Pfeiffer's bacilli to increase the virulence of streptococcus.

M. Danilovich. Typhoid and paratyphoid diseases. The combination of relapsing fever with paratyphus N gives an extremely severe course of the disease, which is accompanied by irregular rises in temperature during the apyretic period and proceeds with signs of septicopyemic damage to the body. Very frequent symptoms of this disease are jaundice, pains in the sacrum and joints, lesions of cartilage, and diarrhea. The mortality rate in relapsing fever complicated by N-paratyphobacillosis can reach 60%. The disruption of the typical temperature curve, especially during the apyretic period, the severe clinical course, hemoculture and culture from feces, urine or pus of the N-paratyphus bacillus, as well as the agglutination reaction in the presence of spirochetes in the blood facilitate diagnosis. Among other infections that combine with relapsing fever, tuberculosis and typhus deserve attention. There are observations that the pulmonary process usually becomes more severe and spreads in the disease febris recurrens. As for typhus, its concurrent course with relapsing fever leads to a change in the characteristic typhus temperature curve, which gives a series of periodic remissions not inherent in typhus. Some clinicians, for example Ignatovsky, believe that the typhus pathogen weakens the virulence of the Obermeier spirochete. Ivashentsev observed an atypical, almost abortive course of typhus in combination with relapsing fever, but other authors (Pletnev, Zavadsky) in numerous observations of the concurrent course of relapsing and typhus fever could not detect any regular or constant effect of one pathogen on the other. The diagnosis of this combination of two diseases should be based, on the one hand, on the presence of Obermeier spirochetes in the blood, and on the other hand, on the clinical picture of typhus, supported by a positive Weil-Felix reaction. Typhus and typhoid fever (resp. paratyphus) occurring simultaneously are actually encountered much less frequently than they are diagnosed. The incorrect diagnosis of such a mixed disease occurs, on the one hand, due to the presence of many similar symptoms of both fevers (including intestinal hemorrhages, which can occur in typhus), and on the other hand, due to the frequently occurring positive Widal reaction in typhus. The serum of a typhus patient quite often, especially in the first days of the disease, gives a positive Widal reaction. Subsequently, the positive Widal reaction usually either becomes negative or is obtained with a lower titer, while the Weil-Felix titer remains either stable or increases. Therefore, the diagnosis of the concurrent course of typhoid and typhus fever cannot in any case be based on a single obtaining of both positive serological reactions even in high titers, but it is necessary, in addition to the clinical picture, to have a stable Weil-Felix reaction and to obtain growth of typhoid or paratyphus bacillus on media from the blood or from feces or urine. It is worth noting the addition of streptococcal or staphylococcal infections in various fevers, which then manifests itself in the appearance of abscesses, phlegmons, parotitis, as well as erysipelas. The addition of erysipelas significantly worsens the general course of the typhoid disease, whether it is typhoid, typhus, or relapsing fever. Moreover, streptococcal infections are often the cause of the development of septic or septicopyemic forms of fevers. Among the combinations of fevers with other diseases, it is necessary to note malaria in typhus with the appearance of characteristic malarial attacks and plasmodia in the blood, as well as infectious colitis, which worsen the MAIN DISEASE AND WEAKEN THE PATIENT. P. Galtsov.